Nicholas Stephanopoulos works with tiny structures so small you can only see them by using powerful microscopes. Some might say he's a builder, but he actually gets the molecules to do the building themselves.

As you go about your day, breathing and thinking, with your heart beating, your body is working. It sends and receives signals, grows, and stores fat, among hundreds of other functions. All of these functions make up your physiology, or how your body works. The same is true for every living animal.

Our oceans are becoming warmer and more acidic. How might these changing conditions put marine food webs in danger?

Some ticks carry a nasty bacteria that they can pass on to humans when they bite. Learn how the health status of the humans they bite helps control what they pass.