THE (A) WARMING OF THE EARTH, WHICH IS PRIMARILY (B) CAUSED BY THE...
21. The (A) warming of the Earth, which is primarily (B) caused by the accumulation of gases, (C) are known
as (D) the greenhouse effect.
21. The (A) warming of the Earth, which is primarily (B) caused by the accumulation of gases, (C) are known
as (D) the greenhouse effect.