Question

the biggest contributor to the decline of the bald eagle was
a global warming.
b destroyed habitats.
c dwindling food supplies.
d poisons.

Explanation:

The decline of the bald eagle was mainly due to the use of pesticides (a type of poison). DDT, a widely - used pesticide, accumulated in the food chain. Eagles, being at the top of the food chain, ingested high levels of DDT. This affected their eggshell thickness (making the eggs more likely to break during incubation), which was a major factor in their population decline.

Answer:

D. poisons