Answer:
Certain plants contain compounds similar to ecdysone which serve as a defense against insects. False
Juvenile hormone levels are high in insect larvae, but must decrease in order for metamorphosis to occur. True.
Chemicals similar to ecdysone and juvenile hormone are widely used commercially to control insect pests. True
Explanation:
The plants produce toxic chemicals such as terpenoids, alkaloids, anthocyanins, phenols, and quinones as a defense against insects. Juvenile hormone levels are high in insect larvae but its concentration decrease when the insect transform into adult stage and in order to occur metamorphosis. Ecdysone and juvenile hormone are widely used as insecticide because it prevents the insects to transform from larva to adult so if they can't mature they can't harm the plants or other things of our environment.