2. Choose the correct variant. ... trees help us to clean ... air. A) A, - B) The, an C)-, the D) -, an5.Choose the correct tense forms.If the air and the water ... polluted,many species of plants and animals ... .a)are,will disappearb)was,have disappearedc)will be,will disappeard)are,disappeared​

Ответ:

The correct answer for the first sentence is (C), the. The word "air" is a non- countable noun, so we don't use "an" before it.

The correct answer for the second sentence is (a) are, will disappear. The condition is present tense, so the verb "will disappear" is also in the present tense. The subject of the sentence is "many species of plants and animals", which is plural, so the verb "disappear" must also be plural.

So the complete sentence would be:

Trees help us to clean the air. If the air and the water are polluted, many species of plants and animals will disappear.

I hope this helps!