[单项选择]Few insects have inspired as much fear and hatred as the diminutive fire ants, less than half an inch long but living in colonies of more than 250,000 others. Everyone in the southern United States gets to know fire ants sooner or later by painful experience. Fire ants live in large earthen mounds and are true social insects--that means they have a caste system (division of labor), with a specialized caste that lays eggs (queen) and a worker caste of sterile females. There are several reasons that they are considered pests. About 60% of people living in areas where fire ants occur are stung every year. Of these, about 1% have some degree of allergic reaction ( called anaphylaxis ) to the sting. Their large mounds are unsightly and can damage mowing equipment. Fire ants sometimes enter electrical and mechanical equipment and can short out switches or chew through insulation. Finally, as fire ants move into new areas, they reduce di
A. They may cause possible mechanical breakdowns to mowing equipment.
B. A person has a 60% chance to be stung by fire ants every year.
C. 1% of the fire ants will cause allergic reactions to the people stung.
D. They will disrupt the food chain by killing off other ants and larger animals.