Answer:
B. Photosynthesis
Step-by-step explanation:
The letter "Z" shown in the diagram above represents the process called photosynthesis. In this process, the plant captures CO2 from the atmosphere and absorbs sunlight, in order to produce all the organic compounds necessary for its development and release oxygen into the environment.
As we can see in the diagram, the plant is absorbing CO2 which is an evidence of the photosynthesis process. This process is the most important biological process we know, because it is essential for the maintenance of life on earth.