Question

Global warming (a) when CO2 and other air pollutants and greenhouse

gases collect within the atmosphere and (b) sunlight and radiation that

have bounced off the earth’s surface.

Normally, this radiation would escape into space — but these pollutants,

which may last for years to centuries within the atmosphere, trap the

warmth and cause the earth to urge hotter. That's what's (c) to as the

atmospheric phenomenon
(a) (i) occurred (ii) occurs (iii) has occurred (d) will occur

(b) (i) absorbed (ii) will absorb (iii) absorbs (d) absorb

(c) (i) refers (ii) referred (iii) refer (d) will refer​​

Answer 1

Answer:

answer is A because they have already occurred