What type of experiment is an observational study? a. in silico b. in vivo c. in vitro d. in utero

Look at the images of different rocks. which rocks have a fine-grained texture? check all that apply. 1 2 3 4 5

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

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