The World's 30,000 Known Species of Spiders ____.​

The world's 30,000 known species of spiders ____.​

A) ​kill more livestock with poisonous bites than any other threat
B) ​have to be controlled in order for integrated pest management to work properly
C) ​are a threat not only to livestock,but also to rural farmers because they nest in sheds where equipment is stored and later retrieved
D) ​kill far more crop-eating insects every year than humans do by using chemicals
E) provide important food for birds that control caterpillar populations​