A Biologist Studied a Population of Squirrels for 15 Years

Multiple Choice

A biologist studied a population of squirrels for 15 years.During that time,the population was never fewer than 30 squirrels and never more than 45.Her data showed that over half of the squirrels born did not survive to reproduce because of both competition for food and predation.In a single generation,90% of the squirrels that were born lived to reproduce,and the population increased to 80.Which inference about this population might be true?

A) The amount of available food may have increased.
B) The parental generation of squirrels developed better eyesight due to improved diet;the subsequent squirrel generation inherited better eyesight.
C) The number of predators that prey upon squirrels may have decreased.
D) There may have been an increase in available food or a decrease in squirrel predation.