What is the purpose of the respiratory system in the body?
A. provides energy for the body
B. filters air and brings oxygen into the body
C. circulates oxygen to tissues in the body
D. provides structure for the body and protects
important organs

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.