Comprehension Passages

208-The passage states that………….. .

A)most of the agricultural crops produced in the USA are lost to pests

B)caterpillars can help plants attacked by black wasps

C)scientists have known all about plants' distress calls for years

***D)friendly insects can help plants against unfriendly ones

E)researchers have only recently become aware of the distress calls of plants

209-According to the passage, further research into the plants' distress calls is necessary in order for scientists…………. .

A)to act promptly when plants need help

B)to develop new chemicals to be used against pests

C)to understand whether plants really have this ability

D)to distinguish between useful and harmful insects

***E)to make use of them in the fight against pests