What is another term for "building blocks"?

How can you approximate the number of calories required to keep you in energy balance?

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

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms