Overpopulation puts severe stress on the environment because . a) more people live in cities b) disease spreads faster c) populations are widely distributed d) competition for resources is greater

What was the land like over 500 million years ago? what was under the sea?

Look at the photo of the leaf. which term best describes this leaf?

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?