2) Acid rain ____ .a) appeared in the 20th centuryb) has always existed in naturec) is the result of industrial development3) ____ is the cause of acid rain.a) Burning coal and oilb) The windc) Water in the air4) A lot of trees have died in Canada because ____ .a) ecological laws of the country are not effectiveb) of the power stations and factoriesc) animals cannot live in polluted environment5) Acid rain badly influences ____ . a) only our fauna b) only our flora c) our habitats