The hypothesis that all modern humans descended from an african lineage has been conclusively proven to be correct is supported by mtdna evidence is supported by evidence from the y chromosome has been proven conclusively correct by y chromosome evidence only. is supported by both mtdna and y chromosome evidence.

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat