Which of the following best describes how the use of DDT led to a serious decline in the brown pelican population of Anacapa Island, California during the 1960s?
1) DDT caused reproductive failure in brown pelicans, leading to a decline in their population.
2) DDT contaminated the food chain, causing bioaccumulation in brown pelicans and leading to their decline.
3) DDT directly killed brown pelicans, resulting in a decrease in their population.
4) DDT caused habitat destruction, leading to a decline in the brown pelican population.