Fact 1: Bottleneck effect occurs when a population suddenly gets much smaller.

Fact 2: Populations are large groups of individuals.

Given the two facts above, answer the question "what suddenly gets much smaller with the bottleneck effect" with the following options: 
- a lot of human deaths
 - tectonic plates being pushed together
 - our nearest star
 - Decreased precipitation
 - Inches or fractions of inches.
 - large groups of individuals
 - the wearing away of rock
 - a hemisphere is tilted away from the sun


 

      large groups of individuals   