It is b because it just is
Answer:
Sorry if I'm wrong but I think it's B
Explanation:
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts or human activities such as specicide and human population planning.
<span>Primary immunodeficiencyvdiseases are a group of more than 250 rare, chronic disorders that affect how the body’s immune system works. Primary immunodeficiency diseases are caused by genetic defects. I hope this helped</span>
