The answer is <span>c. Living organisms modify their environment a little at a time.</span>
The purpose of succession is for an ecosystem to reach balance state right after it is formed or after it is disturbed by man or some disasters. It will increase biodiversity and help to prevent the desertification. Living organisms modify environment a little at a time. By modifying it, they make the environment more suitable for the new species to enter the community.
The concept would be crystallization. As magma cools inside or outside of the earth it crystallizes into an igneous rock. Intrusive (formed inside crust) igneous rocks are typically more course grained and contain many different noticeable minerals (for example, granite). Extrusive (formed outside) igneous rocks are typically more porous and are more fine grained then intrusive rocks (example, obsidian).
Mechanical digestion so breaking down of the food in your mouth. Hope this help :)
Some unicellular organisms are similar to animals because they have the ability to move.
Third option