What does the destruction of the amazon forest threaten the whole world A:The rain forest produces approximately a fifth of the worlds oxygen

B: The deforestation of the rain forest contributes to drought conditions in many countries

C: The rain forest Prevents the spread of polluted air and water to other regions

D: The crops grow in the rain forest Make up much of the worlds food supply

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.