a variable is the right answer
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.
Answer:
It's the nature vs nurture situation. While the genetics of a person does control the physical traits he/she may develop, the environment also has a major role to play here. For instance, the person may have the genes for developing a tall height. If, however, that person is not provided with the right kind of nutrition and the right time, it is very likely that he/she will not grow as tall as they had the potential for. Similar explanation for non-physical traits.
This is not an 'either/or' type of argument. Genetics and the environment have a collective impact in shaping the person into who they are and while the balance may shift to one side or the other in certain cases, it does not cancel out or negate the other's effect.
Hope that answers the question, have a great day!
(4) organisms in a changing environment must adapt to acquire necessary traits and survive
