Which part or parts of the paragraph indicate that oxygen is important to life?
oxygen is the most abundant element on earth. as the largest component of most rock-forming minerals, oxygen comprises 46.6 percent of the mass of earth’s crust and 94 percent of its volume. the human body is mostly water. sixty-five percent of the mass of the human body is oxygen. human beings inhale oxygen and exhale carbon dioxide.

The last two statements of the paragraph i.e "Sixty-five percent of the mass of the human body is oxygen. Human beings inhale oxygen and exhale carbon dioxide." indicates that oxygen is important to life.

Sixty-five percent of the mass of the human body is oxygen

Explanation:

Oxygen is an important element required by the living beings for survival.  Our atmosphere contains 20.95% of oxygen. Oxygen is required for cellular respiration and metabolism in living beings, without oxygen no cell in the body of the organisms will survive. It is necessary for the proper functioning of the cell organelles.

In human beings the oxygen is supplied to all the cells of the body by the circulatory system. Therefore, Sixty-five percent of the mass of the human body is oxygen.