Which facts about the world's rain forests are true?
choose all answers that are correct.
(a)half of the known plant varieties in the world are found in rain forests.
(b)the proportion of earth's landmass covered in rain forests has decreased by 50
percent since 1950.
(c)less than 1 percent of the plants in the rain forests have been tested for
medicinal purposes,
(d)every continent except antarctica has a rain forest.

It is true that half of the known plant varieties in the world are found in rain forests and every continent except Antarctica has a rain forest.

Option A & D

Explanation:

Rain forests in the world are present in almost all the continents of the world mostly in western and central region of Africa, in southern part of America, in Asia and in Australia also. But there is no portion of rain forests which are found in the continent of Antarctica.

Since it is present in so many parts of the world therefore it is home to a large number of species of animals and plants found all over the world. Around about 50% of the plant varieties in the world are found in the rain forests.