Which sentence best summarizes a central idea of the text?
A
Burger discovered that smaller animals tended to live longer because they were able to hide
or hibernate.
B
Some scientists disagree with Burger's analysis about the factors involved in a species'
overall survival rate.
© When Burger studied the lifespan of ancient animals, he found 19 types of mammals that
lasted 20 million years.
D
Burger determined that the survival of a species largely depended on a combination of
genetic traits and a stable environment.