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Cinnamon, spice and ‘everything nice’ – why lead-tainted cinnamon products have turned up on shelves, and what questions consumers should ask

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theconversation.com – Katarzyna Kordas, Associate Professor of Epidemiology and Environmental Health, University at Buffalo – 2024-11-27 07:23:00

It’s important to buy cinnamon from reputable dealers.

Anjelika Gretskaia/Moment via Getty Images

Katarzyna Kordas, University at Buffalo

Spices bring up feelings of comfort, cultural belonging and holidays. They can make our homes smell amazing and our food taste delicious. They can satisfy our cravings, expand our culinary horizons and help us eat things that we might normally dislike. Spices have health-enhancing properties and, in medicine, have been used to heal people since the ancient times.

Recently, however, spices have been getting a bad rep.

In September 2024, Consumer Reports, a nonprofit organization created to inform consumers about products sold in the U.S., investigated more than three dozen ground cinnamon products and found that 1 in 3 contained lead levels above 1 part per million, enough to trigger a recall in New York, one U.S. state that has published guidelines for heavy metals in spices.

The Food and Drug Administration issued three alerts throughout 2024, warning consumers about lead in certain brands of cinnamon products. Such notices rightfully put consumers on alert and have people wondering if the spice products they buy are safe – or not.

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A Consumer Reports investigation of more than three dozen ground cinnamon products found that 1 in 3 contain lead levels above 1 part per million.

As an environmental epidemiologist with training in nutritional sciences, I have investigated the relationship between nutritional status, diets and heavy metal exposures in children.

There are several things consumers should be thinking about when it comes to lead – and other heavy metals – in cinnamon.

Why is lead found in cinnamon?

Most people are familiar with cinnamon in two forms – sticks and ground spice. Both come from the dried inner bark of the cinnamon tree, which is harvested after a few years of cultivation. For the U.S. market, cinnamon is largely imported from Indonesia, Vietnam, Sri Lanka, India and China.

One way that lead could accumulate in cinnamon tree bark is when trees are cultivated in contaminated soil. Lead can also be introduced in cinnamon products during processing, such as grinding.

When ground cinnamon is prepared, some producers may add lead compounds intentionally to enhance the weight or color of the product and, thus, fetch a higher sale price. This is known as “food adulteration,” and products with known or suspected adulteration are refused entry into the U.S.

However, in the fall of 2023, approximately 600 cases of elevated blood lead levels in the U.S., defined as levels equal to or above 3.5 micrograms per deciliter – mostly among children – were linked to the consumption of certain brands of cinnamon apple sauce. The levels of lead in cinnamon used to manufacture those products ranged from 2,270 to 5,110 parts per million, indicating food adulteration. The manufacturing plant was investigated by the FDA.

Horizontal photo of cinnamon trees, with trunks in foreground.

Cinnamon trees in Zanzibar, Tanzania. Zanzibar is known the world over as the ‘spice islands.’

Dong Jianghui/Xinhua via Getty Images

More broadly, spices purchased from vendors in the U.S. have lower lead levels than those sold abroad.

There is some evidence that cinnamon sticks have lower lead levels than ground spice. Lead levels in ground cinnamon sold in the U.S. and analyzed by Consumer Reports ranged from 0.02 to 3.52 parts per million. These levels were at least 1,500 times lower than in the adulterated cinnamon.

There are no federal guidelines for lead or other heavy metals in spices. New York state has proposed even stricter guidelines than its current level of 1 part per million, which would allow the New York Department of Agriculture and Markets to remove products from commerce if lead levels exceed 0.21 parts per million.

What does it mean that ‘the dose makes the poison’?

The current FDA guideline on daily intake of lead from diets overall is to limit lead intake to 2.2 micrograms per day for children. For women of reproductive age, this value is 8.8 micrograms.

The lead dose we are exposed to from foods depends on the level of lead in the food and how much of that food we eat. Higher doses mean more potential harm. The frequency with which we consume foods – meaning daily versus occasionally – also matters.

For spices like cinnamon, the amount and frequency of consumption depends on cultural traditions and personal preference. For many, cinnamon is a seasonal spice; others use it year-round in savory dishes or sauces.

Cinnamon is beloved in baked goods. Take a cinnamon roll recipe calling for 1.5 tablespoons (slightly less than 12 grams) of the spice. If a recipe yields 12 rolls, each will have around 1 gram of cinnamon. In the Consumer Reports investigation, some cinnamon products were classified as “okay to use” or “best to use.”

The highest value of lead in cinnamon products in the “okay to use” category was 0.87 parts per million, and in the “best to use” category, it was 0.15 parts per million. A child would have to consume 2.5 or more rolls made with the “okay to use” cinnamon to exceed the FDA guideline on limiting lead intake from foods to 2.2 micrograms per day, assuming that no other food contained lead. To exceed this guideline with “best to use” cinnamon, a child would have to eat 15 or more rolls.

Stick cinnamon and cinnamon powder on rustic wooden table.

Research suggests that ground cinnamon contains higher lead levels than cinnamon sticks.

Helen Camacaro/Moment via Getty Images

Can cinnamon contribute to elevated blood lead levels?

Because of lead’s effects on development in early life, the greatest concern is for exposure in young children and pregnant women. Lead is absorbed in the small intestine, where it can latch onto cellular receptors that evolved to carry iron and other metals.

The impact of a contaminated spice on a person’s blood lead level depends on the dose of exposure and the proportion of lead available for intestinal absorption. For several spices, the proportion of available lead was 49%, which means that about half of the lead that is ingested will be absorbed.

Lead absorption is higher after a fast of three hours or more, and skipping breakfast may contribute to higher blood lead levels in children.

People who have nutritional deficiencies, such as iron deficiency, also tend to absorb more lead and have higher blood lead levels. This is because our bodies compensate for the deficiency by producing more receptors to capture iron from foods. Lead takes advantage of the additional receptors to enter the body. Young children and pregnant women are at higher risk for developing iron deficiency, so there is good reason for vigilance about lead in the foods they consume.

Studies show that among children with lead poisoning in the U.S., contaminated spices were one of several sources of lead exposure. Studies that estimate blood lead levels from statistical models suggest that consuming 5 micrograms of lead or more from spices daily could substantially contribute to elevated blood lead levels.

For occasional or seasonal consumption, or lower levels of contamination, more research is needed to understand how lead in spices would affect lead levels in the blood.

For people who have other sources of lead in their homes, jobs or hobbies, additional lead from foods or spices may matter more because it adds to the cumulative dose from multiple exposure sources.

How to test for elevated blood lead levels

The Centers for Disease Control and Prevention recommends that children at risk for lead exposure get a blood lead test at 1 and 2 years of age. Older children can also get tested. Finger-prick screening tests are often available in pediatric offices, but results may need to be confirmed in venous blood if the screening result was elevated.

Adults in the U.S. are not routinely tested for lead exposure, but concerned couples who plan on having children should talk to their health care providers.

What to consider when using or buying cinnamon or other spices

If the product is on an FDA Alert or the Consumer Reports “don’t use” list, discard it.

Other questions to consider are:

  • Does your household use spices frequently and in large amounts?
  • Do young children or pregnant women in your household consume spices?
  • Do you typically consume spices on breakfast foods or beverages?

If the answer to any of these questions is yes, then buy good-quality products, from large, reputable sellers. Think about using cinnamon sticks if possible.

And continue to enjoy spices!The Conversation

Katarzyna Kordas, Associate Professor of Epidemiology and Environmental Health, University at Buffalo

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The Conversation

Colors are objective, according to two philosophers − even though the blue you see doesn’t match what I see

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theconversation.com – Elay Shech, Professor of Philosophy, Auburn University – 2025-04-25 07:55:00

What appear to be blue and green spirals are actually the same color.
Akiyoshi Kitaoka

Elay Shech, Auburn University and Michael Watkins, Auburn University

Is your green my green? Probably not. What appears as pure green to me will likely look a bit yellowish or blueish to you. This is because visual systems vary from person to person. Moreover, an object’s color may appear differently against different backgrounds or under different lighting.

These facts might naturally lead you to think that colors are subjective. That, unlike features such as length and temperature, colors are not objective features. Either nothing has a true color, or colors are relative to observers and their viewing conditions.

But perceptual variation has misled you. We are philosophers who study colors, objectivity and science, and we argue in our book “The Metaphysics of Colors” that colors are as objective as length and temperature.

Perceptual variation

There is a surprising amount of variation in how people perceive the world. If you offer a group of people a spectrum of color chips ranging from chartreuse to purple and asked them to pick the unique green chip – the chip with no yellow or blue in it – their choices would vary considerably. Indeed, there wouldn’t be a single chip that most observers would agree is unique green.

Generally, an object’s background can result in dramatic changes in how you perceive its colors. If you place a gray object against a lighter background, it will appear darker than if you place it against a darker background. This variation in perception is perhaps most striking when viewing an object under different lighting, where a red apple could look green or blue.

Of course, that you experience something differently does not prove that what is experienced is not objective. Water that feels cold to one person may not feel cold to another. And although we do not know who is feeling the water “correctly,” or whether that question even makes sense, we can know the temperature of the water and presume that this temperature is independent of your experience.

Similarly, that you can change the appearance of something’s color is not the same as changing its color. You can make an apple look green or blue, but that is not evidence that the apple is not red.

Apple under a gradient of red to blue light
Under different lighting conditions, objects take on different colors.
Gyozo Vaczi/iStock via Getty Images Plus

For comparison, the Moon appears larger when it’s on the horizon than when it appears near its zenith. But the size of the Moon has not changed, only its appearance. Hence, that the appearance of an object’s color or size varies is, by itself, no reason to think that its color and size are not objective features of the object. In other words, the properties of an object are independent of how they appear to you.

That said, given that there is so much variation in how objects appear, how do you determine what color something actually is? Is there a way to determine the color of something despite the many different experiences you might have of it?

Matching colors

Perhaps determining the color of something is to determine whether it is red or blue. But we suggest a different approach. Notice that squares that appear to be the same shade of pink against different backgrounds look different against the same background.

Green, purple and orange squares with smaller squares in shades of pink placed at their centers and at the bottom of the image
The smaller squares may appear to be the same color, but if you compare them with the strip of squares at the bottom, they’re actually different shades.
Shobdohin/Wikimedia Commons, CC BY-SA

It’s easy to assume that to prove colors are objective would require knowing which observers, lighting conditions and backgrounds are the best, or “normal.” But determining the right observers and viewing conditions is not required for determining the very specific color of an object, regardless of its name. And it is not required to determine whether two objects have the same color.

To determine whether two objects have the same color, an observer would need to view the objects side by side against the same background and under various lighting conditions. If you painted part of a room and find that you don’t have enough paint, for instance, finding a match might be very tricky. A color match requires that no observer under any lighting condition will see a difference between the new paint and the old.

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Is the dress yellow and white or black and blue?

That two people can determine whether two objects have the same color even if they don’t agree on exactly what that color is – just as a pool of water can have a particular temperature without feeling the same to me and you – seems like compelling evidence to us that colors are objective features of our world.

Colors, science and indispensability

Everyday interactions with colors – such as matching paint samples, determining whether your shirt and pants clash, and even your ability to interpret works of art – are hard to explain if colors are not objective features of objects. But if you turn to science and look at the many ways that researchers think about colors, it becomes harder still.

For example, in the field of color science, scientific laws are used to explain how objects and light affect perception and the colors of other objects. Such laws, for instance, predict what happens when you mix colored pigments, when you view contrasting colors simultaneously or successively, and when you look at colored objects in various lighting conditions.

The philosophers Hilary Putnam and Willard van Orman Quine made famous what is known as the indispensability argument. The basic idea is that if something is indispensable to science, then it must be real and objective – otherwise, science wouldn’t work as well as it does.

For example, you may wonder whether unobservable entities such as electrons and electromagnetic fields really exist. But, so the argument goes, the best scientific explanations assume the existence of such entities and so they must exist. Similarly, because mathematics is indispensable to contemporary science, some philosophers argue that this means mathematical objects are objective and exist independently of a person’s mind.

Blue damselfish, seeming iridescent against a black background
The color of an animal can exert evolutionary pressure.
Paul Starosta/Stone via Getty Images

Likewise, we suggest that color plays an indispensable role in evolutionary biology. For example, researchers have argued that aposematism – the use of colors to signal a warning for predators – also benefits an animal’s ability to gather resources. Here, an animal’s coloration works directly to expand its food-gathering niche insofar as it informs potential predators that the animal is poisonous or venomous.

In fact, animals can exploit the fact that the same color pattern can be perceived differently by different perceivers. For instance, some damselfish have ultraviolet face patterns that help them be recognized by other members of their species and communicate with potential mates while remaining largely hidden to predators unable to perceive ultraviolet colors.

In sum, our ability to determine whether objects are colored the same or differently and the indispensable roles they play in science suggest that colors are as real and objective as length and temperature.The Conversation

Elay Shech, Professor of Philosophy, Auburn University and Michael Watkins, Professor of Philosophy, Auburn University

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Perfect brownies baked at high altitude are possible thanks to Colorado’s home economics pioneer Inga Allison

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theconversation.com – Tobi Jacobi, Professor of English, Colorado State University – 2025-04-22 07:47:00

Students work in the high-altitude baking laboratory.
Archives and Special Collections, Colorado State University

Tobi Jacobi, Colorado State University and Caitlin Clark, Colorado State University

Many bakers working at high altitudes have carefully followed a standard recipe only to reach into the oven to find a sunken cake, flat cookies or dry muffins.

Experienced mountain bakers know they need a few tricks to achieve the same results as their fellow artisans working at sea level.

These tricks are more than family lore, however. They originated in the early 20th century thanks to research on high-altitude baking done by Inga Allison, then a professor at Colorado State University. It was Allison’s scientific prowess and experimentation that brought us the possibility of perfect high-altitude brownies and other baked goods.

A recipe for brownies at high altitude.
Inga Allison’s high-altitude brownie recipe.
Archives and Special Collections, Colorado State University

We are two current academics at CSU whose work has been touched by Allison’s legacy.

One of us – Caitlin Clark – still relies on Allison’s lessons a century later in her work as a food scientist in Colorado. The other – Tobi Jacobi – is a scholar of women’s rhetoric and community writing, and an enthusiastic home baker in the Rocky Mountains, who learned about Allison while conducting archival research on women’s work and leadership at CSU.

That research developed into “Knowing Her,” an exhibition Jacobi developed with Suzanne Faris, a CSU sculpture professor. The exhibit highlights dozens of women across 100 years of women’s work and leadership at CSU and will be on display through mid-August 2025 in the CSU Fort Collins campus Morgan Library.

A pioneer in home economics

Inga Allison is one of the fascinating and accomplished women who is part of the exhibit.

Allison was born in 1876 in Illinois and attended the University of Chicago, where she completed the prestigious “science course” work that heavily influenced her career trajectory. Her studies and research also set the stage for her belief that women’s education was more than preparation for domestic life.

In 1908, Allison was hired as a faculty member in home economics at Colorado Agricultural College, which is now CSU. She joined a group of faculty who were beginning to study the effects of altitude on baking and crop growth. The department was located inside Guggenheim Hall, a building that was constructed for home economics education but lacked lab equipment or serious research materials.

A sepia-toned photograph of Inga Allison, a white woman in dark clothes with her hair pulled back.
Inga Allison was a professor of home economics at Colorado Agricultural College, where she developed recipes that worked in high altitudes.
Archives and Special Collections, Colorado State University

Allison took both the land grant mission of the university with its focus on teaching, research and extension and her particular charge to prepare women for the future seriously. She urged her students to move beyond simple conceptions of home economics as mere preparation for domestic life. She wanted them to engage with the physical, biological and social sciences to understand the larger context for home economics work.

Such thinking, according to CSU historian James E. Hansen, pushed women college students in the early 20th century to expand the reach of home economics to include “extension and welfare work, dietetics, institutional management, laboratory research work, child development and teaching.”

News articles from the early 1900s track Allison giving lectures like “The Economic Side of Natural Living” to the Colorado Health Club and talks on domestic science to ladies clubs and at schools across Colorado. One of her talks in 1910 focused on the art of dishwashing.

Allison became the home economics department chair in 1910 and eventually dean. In this leadership role, she urged then-CSU President Charles Lory to fund lab materials for the home economics department. It took 19 years for this dream to come to fruition.

In the meantime, Allison collaborated with Lory, who gave her access to lab equipment in the physics department. She pieced together equipment to conduct research on the relationship between cooking foods in water and atmospheric pressure, but systematic control of heat, temperature and pressure was difficult to achieve.

She sought other ways to conduct high-altitude experiments and traveled across Colorado where she worked with students to test baking recipes in varied conditions, including at 11,797 feet in a shelter house on Fall River Road near Estes Park.

Early 1900s car traveling in the Rocky Mountains.
Inga Allison tested her high-altitude baking recipes at 11,797 feet at the shelter house on Fall River Road, near Estes Park, Colorado.
Archives and Special Collections, Colorado State University

But Allison realized that recipes baked at 5,000 feet in Fort Collins and Denver simply didn’t work in higher altitudes. Little advancement in baking methods occurred until 1927, when the first altitude baking lab in the nation was constructed at CSU thanks to Allison’s research. The results were tangible — and tasty — as public dissemination of altitude-specific baking practices began.

A 1932 bulletin on baking at altitude offers hundreds of formulas for success at heights ranging from 4,000 feet to over 11,000 feet. Its author, Marjorie Peterson, a home economics staff person at the Colorado Experiment Station, credits Allison for her constructive suggestions and support in the development of the booklet.

Science of high-altitude baking

As a senior food scientist in a mountain state, one of us – Caitlin Clark – advises bakers on how to adjust their recipes to compensate for altitude. Thanks to Allison’s research, bakers at high altitude today can anticipate how the lower air pressure will affect their recipes and compensate by making small adjustments.

The first thing you have to understand before heading into the kitchen is that the higher the altitude, the lower the air pressure. This lower pressure has chemical and physical effects on baking.

Air pressure is a force that pushes back on all of the molecules in a system and prevents them from venturing off into the environment. Heat plays the opposite role – it adds energy and pushes molecules to escape.

When water is boiled, molecules escape by turning into steam. The less air pressure is pushing back, the less energy is required to make this happen. That’s why water boils at lower temperatures at higher altitudes – around 200 degrees Fahrenheit in Denver compared with 212 F at sea level.

So, when baking is done at high altitude, steam is produced at a lower temperature and earlier in the baking time. Carbon dioxide produced by leavening agents also expands more rapidly in the thinner air. This causes high-altitude baked goods to rise too early, before their structure has fully set, leading to collapsed cakes and flat muffins. Finally, the rapid evaporation of water leads to over-concentration of sugars and fats in the recipe, which can cause pastries to have a gummy, undesirable texture.

Allison learned that high-altitude bakers could adjust to their environment by reducing the amount of sugar or increasing liquids to prevent over-concentration, and using less of leavening agents like baking soda or baking powder to prevent dough from rising too quickly.

Allison was one of many groundbreaking women in the early 20th century who actively supported higher education for women and advanced research in science, politics, humanities and education in Colorado.

Others included Grace Espy-Patton, a professor of English and sociology at CSU from 1885 to 1896 who founded an early feminist journal and was the first woman to register to vote in Fort Collins. Miriam Palmer was an aphid specialist and master illustrator whose work crafting hyper-realistic wax apples in the early 1900s allowed farmers to confirm rediscovery of the lost Colorado Orange apple, a fruit that has been successfully propagated in recent years.

In 1945, Allison retired as both an emerita professor and emerita dean at CSU. She immediately stepped into the role of student and took classes in Russian and biochemistry.

In the fall of 1958, CSU opened a new dormitory for women that was named Allison Hall in her honor.

“I had supposed that such a thing happened only to the very rich or the very dead,” Allison told reporters at the dedication ceremony.

Read more of our stories about Colorado.The Conversation

Tobi Jacobi, Professor of English, Colorado State University and Caitlin Clark, Senior Food Scientist at the CSU Spur Food Innovation Center, Colorado State University

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Why don’t humans have hair all over their bodies? A biologist explains our lack of fur

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theconversation.com – Maria Chikina, Assistant Professor of Computational and Systems Biology, University of Pittsburgh – 2025-04-21 07:33:00

Some mammals are super hairy, some are not.
Ed Jones/AFP via Getty Images

Maria Chikina, University of Pittsburgh

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.


Why don’t humans have hair all over their bodies like other animals? – Murilo, age 5, Brazil


Have you ever wondered why you don’t have thick hair covering your whole body like a dog, cat or gorilla does?

Humans aren’t the only mammals with sparse hair. Elephants, rhinos and naked mole rats also have very little hair. It’s true for some marine mammals, such as whales and dolphins, too.

Scientists think the earliest mammals, which lived at the time of the dinosaurs, were quite hairy. But over hundreds of millions of years, a small handful of mammals, including humans, evolved to have less hair. What’s the advantage of not growing your own fur coat?

I’m a biologist who studies the genes that control hairiness in mammals. Why humans and a small number of other mammals are relatively hairless is an interesting question. It all comes down to whether certain genes are turned on or off.

Hair benefits

Hair and fur have many important jobs. They keep animals warm, protect their skin from the sun and injuries and help them blend into their surroundings.

They even assist animals in sensing their environment. Ever felt a tickle when something almost touches you? That’s your hair helping you detect things nearby.

Humans do have hair all over their bodies, but it is generally sparser and finer than that of our hairier relatives. A notable exception is the hair on our heads, which likely serves to protect the scalp from the sun. In human adults, the thicker hair that develops under the arms and between the legs likely reduces skin friction and aids in cooling by dispersing sweat.

So hair can be pretty beneficial. There must have been a strong evolutionary reason for people to lose so much of it.

Why humans lost their hair

The story begins about 7 million years ago, when humans and chimpanzees took different evolutionary paths. Although scientists can’t be sure why humans became less hairy, we have some strong theories that involve sweat.

Humans have far more sweat glands than chimps and other mammals do. Sweating keeps you cool. As sweat evaporates from your skin, heat energy is carried away from your body. This cooling system was likely crucial for early human ancestors, who lived in the hot African savanna.

Of course, there are plenty of mammals living in hot climates right now that are covered with fur. Early humans were able to hunt those kinds of animals by tiring them out over long chases in the heat – a strategy known as persistence hunting.

Humans didn’t need to be faster than the animals they hunted. They just needed to keep going until their prey got too hot and tired to flee. Being able to sweat a lot, without a thick coat of hair, made this endurance possible.

Genes that control hairiness

To better understand hairiness in mammals, my research team compared the genetic information of 62 different mammals, from humans to armadillos to dogs and squirrels. By lining up the DNA of all these different species, we were able to zero in on the genes linked to keeping or losing body hair.

Among the many discoveries we made, we learned humans still carry all the genes needed for a full coat of hair – they are just muted or switched off.

In the story of “Beauty and the Beast,” the Beast is covered in thick fur, which might seem like pure fantasy. But in real life some rare conditions can cause people to grow a lot of hair all over their bodies. This condition, called hypertrichosis, is very unusual and has been called “werewolf syndrome” because of how people who have it look.

A detailed painting of a man and a woman standing next to one another in historical looking clothes. The man's face is covered in hair, while the woman's is not.
Petrus Gonsalvus and his wife, Catherine, painted by Joris Hoefnagel, circa 1575.
National Gallery of Art

In the 1500s, a Spanish man named Petrus Gonsalvus was born with hypertrichosis. As a child he was sent in an iron cage like an animal to Henry II of France as a gift. It wasn’t long before the king realized Petrus was like any other person and could be educated. In time, he married a lady, forming the inspiration for the “Beauty and the Beast” story.

While you will probably never meet someone with this rare trait, it shows how genes can lead to unique and surprising changes in hair growth.


Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.The Conversation

Maria Chikina, Assistant Professor of Computational and Systems Biology, University of Pittsburgh

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