From what sources are people most likely exposed to BPA? What external factors, or conditions, affect the release of BPA from those sources?
How can people reduce their exposure to BPA?
Should BPA be kept out of products that people frequently use? Why or why not?

What is thought to have caused the mass extinction at the end of the cretaceous period?

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?