As we are still unable to prove it fully.
Answer:
Secondary succession is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat. Examples include areas which have been cleared of existing vegetation (such as after tree-felling in a woodland) and destructive events such as fires.
Answer:
C. Mutation.
Explanation:
The mutation is the source of all genetic variation. There are two types of mutations. One is the natural mutation, and another is the artificial mutation. The natural mutation occurs due to the environmental cause, and humans using various mutagens do artificial mutations.
These two types of mutations always bring variation in any organism. This variation can be positive or can be negative too. Natural mutation is not possible to control so that anything can happen. Either positive or negative changes can occur. But in the case of artificial mutation, in 90% cases, positive results come in genetic variation.
The primary function of the plasma membrane is to protect the cell from its surroundings. Composed of a phospholipid bilayer with embedded proteins, the plasma membrane is selectively permeable to ions and organic molecules and regulates the movement of substances in and out of cells.
