DDT is a pesticide that was once widely used to control agricultural
pests and mosquitoes. However, this pesticide caused the eggshells of
certain birds, including the brown pelican, to become fragile and thin. The
adults would then accidentally crush the eggs while trying to incubate
them. What happened to brown pelican populations as a result of DDT use by
humans? *
Mark only one oval.

1) The populations increased much more slowly.
2) The populations decreased as fewer eggs survived long enough to hatch.
3) The populations remained stable over time.
4) The populations increased as pelicans laid more eggs so that more offspring would
survive.