A long-lasting pesticide is sprayed on a crop area to kill insects over a period of 20 years. During that time, local populations of birds and small mammals decline somewhat, and hawks, which prey on smaller birds and small mammals, show serious population declines. If, as ecologists think, the population changes are due to pesticides, which result of pesticide use is most likely to blame?
O Uptake of pesticides by the crops
@ Decline in insect populations
O Biomagnification
O Pollution of water by pesticide runoff