Phytoplankton produces
of the oxygen we breathe?

A byproduct of photosynthesis is oxygen. Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth's atmosphere. In the lab, scientists can determine how much oxygen is produced by a single phytoplankton cell.

correct answer is a. and d.

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.