Question: Wolves, which are top predators, were eliminated from Yellowstone National Park in the 1930s. In 1995, wolves were reintroduced into Yellowstone. During the period in which wolves were absent from Yellowstone, which most likely occurred?

  Options: 
 A. an increase in competition for food resources among small prey
 B. a greater opportunity for primary producers to flourish
 C. an increase in the population of tertiary consumers
 D. a greater balance of predator-prey relationships 
Answer: A