All of these are essential to survive
I think the answer is A. Competition. :)
Answer:
There are four steps in secondary Succession.
1.
1st year after forest fire, flood, or farmer abandons a field: Weeds grow,
usually crabgrass.
2.
2nd year: Seeds blown in or carried in by animals become new weedy
plants, such as horse-weed.
3.
5 to 15 years: Small pines begin growing in the area, gradually become a
pine forest
4.
As older pines die hardwoods succeed them if the climate supports them.
Explanation:
D) higher density than water