If bottleneck effect occurs when large groups of individuals suddenly gets much smaller, then what suddenly gets much smaller with the bottleneck effect?

Answer choices:
- 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    