Question

which factor would most likely cause a population decrease?
specialized niche
high birth rate
stable chemical conditions
ability to avoid predators

Explanation:

A specialized niche means the population is adapted to a very specific environment. If that environment changes (which is common in nature), the population may not be able to adapt quickly enough, leading to a decrease. A high birth rate would likely increase the population. Stable chemical conditions are a positive for population survival (not a cause of decrease). The ability to avoid predators helps the population survive (not decrease).

Answer:

specialized niche