What are the five main layers of the atmosphere and which is closest to earth?

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?

Migration is a. the movement of organisms from a native location to a foreign location b. the movement of organisms from a foreign location to a native location the movement of organisms from their water supply to their food supply d. the seasonal movement of organisms between locations c. select the best answer from above

Which structure in the cardiovascular system connect arteries to veins?