70 points please actually answer or i’ll report. question in pic

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

Cells destroy body cells infected by a virus or bacteria. killer t t memory t none of the above

What substance acts to prevent sudden ph changes in bodily fluids?