False we are made out of A lot of different Troyes of cells
An example where space would be a limiting factor would be this: Wolves live in a very good habitat for them - there are plenty of animals to be found and eaten. However, because their current habitat is rather limited, they cannot expand beyond a certain size because otherwise they would interfere with the habitat of each other and also reduce the amount of necessary food in the environment.
Bio accumulation of DDT lead to bird eggs with weak shells and non viable offspring. The lethal effects of DDT on birds was first noted in 1950; scientists discovered that earthworm was accumulating the DDT pesticide and that the robins that were preying on the earthworms were been poisoned. Further research revealed that the chemical cause thinning of the egg shell and production of non viable offspring. The chemical has since been banned in USA.
I would say B is the answer because Athlete's Foot is an infection, African Sleeping Sickness is caused by a parasitic disease, and tuberculosis is a disease.