What is the function of the structure labeled A in the diagram below? A. To protect the delicate tissue of the lungs

B. To exchange gases between the lungs and blood vessels

C. To contract, thus causing the chest cavity to enlarge

D. To chemically digest food exiting the esophagus

Which statement is true about the cell theory? a) it is well-supported by evidence. b) it is unchangeable and permanent.

How do tides affect the organisms living in intertidal zones? a. no organisms live in intertidal zones due to the tumultuous environment. b. the mechanical forces of the waves keeps the organisms clean. c. only plants live in intertidal zones because the animals float away with the waves and never return. d. the mechanical forces of the waves can dislodge the organisms from their habitat.

In the water cycle , when does water undergo a chemical change