Aparticular region experiences low average temperatures year-round, receives very little precipitation, and supports only small plants and a few animal species. to which major biome type does this region most likely belong?

This region is most likely a part of the tundra biome. Tundra biomes can have the conditions that are listed such as low average temperatures year round, very little precipitation, and this region supports only small plants and a few animal species. Specifically plant life in Tundra regions are usually low to the ground with very few trees because of the flat area and the harsh winds that blow through these regions. This region is also most likely an arctic tundra due to the very low temperatures. 

Brazzaville and kinshasha, luanda,librevilleand and monrovia.

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.