1. brain is the main organ of this system respiratory system 2. produces hormones endocrine system 3. breaks food down for body's use excretory system 4. sends nutrients to all the body's cells circulatory system 5. provides structure for the body nervous system 6. provides support and movement digestive system 7. kidneys are the main organs of this system muscular system 8. lungs are the primary organs of this system skeletal system

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.