NASA is looking for a kind of plant that will absorb carbon dioxide, release oxygen, and provide the space colonists with food to eat. Use your textbook to research the characteristics of the three different kinds of plants. Which kind do you believe will do the best job of supporting the Mars explorers? Explain your answer.

12) several teeth were found in an area of flat land covered with trees and plants. the teeth were examined by a paleontologist, and it was determined that the teeth came from a shark. they found many other shark teeth in this area. however, the people who discovered the teeth were puzzled, because there was no source of water near where the fossils were found. what is the paleontologist's best explanation for why the teeth were found in this area? a) sharks used to live on flat land. b) this area was once covered with salt water. c) this area was once covered with freshwater. d) someone buried the shark teeth deep in the ground.