Answer: a
Explanation:
Because the top predictors only eat meat, and not the plants, so if you take out the primary consumers, then the top predictors will begin to die out.
The main food sources of the birds( the plentiful recourses within the environment occupied by the species)
Traits favorable for survival
The vas deferens are a fibromuscular tube which connect to the epididymis, and is an excretory duct of the testis.
Hope I could help! :)