Not many trees grow in the tundra because
(A) it doesnt receive enough rainfall
(B) the permafrost prevents proper water infiltration
(C) it is too cold
(D) the soil contains chemicals excreted by lichens that prevent tree growth
(A) and (B) are the correct answers. (C) isnt true because there are trees in other biomes adapted to extremely cold conditions. And (D) isnt true at all.