If each level in a food chain typically loses 90 percent of the energy it takes in, and the producer level uses 1000 kcal of energy, how much of that energy is left after the third trophic level

The portions of an antibody molecule that interact with antigen are known as

Which is the path of sperm from the testes to the urethra?

What biome does the capuchin monkey live in

Which is a valve between the right atrium and the right ventricle of the heart that directs blood that needs oxygen to the lungs.

How long does it take for a body to decompose?

Since mature red blood cells do not contain a nucleus, more room is available for what?

What does a cladogram show about organisms?

What is the most efficient enzyme known that can catalyze hydrogen?

The process where sediments turn into a sedimentary rock through compaction or cementation is called

Muscles in animals are often found in pairs, because A. muscles need to be able to both push and pull. B. muscles can only push. C. muscles can only produce a force as they relax. D. muscles can only pull.