Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Plants need this waxy outer coating, also known as a cuticle, for a
variety of reasons. The cuticle keeps the important things the plant
needs in, such as water and carbon dioxide, and the things the plant
doesn't need, such as too much heat, out. It performs a few different
functions, including protecting the important cells needed for
photosynthesis.
Answer:
A. decomposers transfer nutrients back to the soil