Which of Earth's spheres are involved in the water cycle? A. Atmosphere, lithosphere, and hydrosphere only
B. Atmosphere, lithosphere, hydrosphere, and biosphere
C. Atmosphere, hydrosphere, and biosphere only
O D. Atmosphere and lithosphere only

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

What are genotypes? what are phenotypes?

The similarities of organisms in which two areas numbered above provide the best evidence for common ancestry between organisms in both locations?