Answer:
<em>Respiration and photosynthesis. </em>
Explanation:
<em>Respiration provides the cell with oxygen while photosynthesis provides it with carbon dioxide. Both functions release what is needed for the other. Therefore, these functions interact.</em>
In secondary succession, the pioneer species are plants that are adapted to exploit disturbances rather than bare rock. They typically include plants such as grasses, birch trees, and fireweed. Organic matter from the pioneer species improves the soil so other trees and plants can move into the area.
3: B Nervous system. 4: A Sensing and responding to its external environment.
<span>A Simple Compound Microscope</span>
