Question

Which hypothesis best explains why, relative to their sizes, a rabbit must eat a greater volume of food than a hippopotamus?
A. Rabbits run faster than hippopotamuses.
B. Rabbits lose heat more easily due to their relatively larger surface area.
C. Rabbits are prey, and therefore require more stored energy.
D. Hippopotamuses inhabit only hot climates.
E. Hippopotamuses spend significant amounts of time in water.

Answer 1

the "relative to their sizes" part is stumping me.

Answer 2

C

Answer 3

that is one of my guesses, but it doesn't have anything to do with size though. what is your reasoning?

Answer 4

I think that B is the correct answer - if you work out how much food is consumed per kilo of body weight for a rabbit and a hippo then you'd find the rabbit ate more, or to put it another way, 1 hippo eats less than 1000 rabbits (I guess that's how many rabbits would weigh as much as one hippo). This is what they mean by relative to their sizes.

This is because the surface area to volume is far greater for a small animal than a large one - the surface area of a sphere increases according to the square of the radius whereas the volume increases according to the cube of the radius, so as the radius increases the surface area increases more slowly than the volume. So the reasons to be big, from an evolutionary point of view, are to lose heat less rapidly or to stop other things eating you for breakfast. This might explain why polar bears are bigger than the grizzly bears found further south.