Which example could be evidence for an organism's growth being influenced by the organism's genes?
 A. 
Vegetation grows at different rates depending on the available water supply.
 B. 
A hamster species can be made smaller by mating together only small hamsters.
 C. 
Orchids grown in a greenhouse are smaller than orchids grown in the wild.
 D. 
A cat that eats more food will grow to be larger than a cat that eat less food.