A wildlife biologist is studying a population of penguins at the South Pole. These penguins are endangered by global warming and the destruction of their habitat. How will natural selection produce change in the penguins? a. Natural selection will only act upon the penguins with harmful traits and produce increasingly disadvantageous changes over several generation.

b. Natural selection will act upon each penguin individually to produce advantageous changes within one generation.

c. Natural selection will only act upon the penguins with advantageous traits and produce increasingly disadvantageous changes within two generations.

d. Natural selection will act upon the entire population of penguins to produce advantageous changes over several generations.