Hadean is the first eon of precambrian, and took place around 4.6 and 4.0 billion years ago.
D because they are complete systems
The answer is survival
This is the ceasing of the existence of any particular species. ... A condition in which two populations of the same species, over time, can no longer breed with each other to produce live offspring. Survival. This is the set of skills and abilities necessary for an organism to live. If you’re looking for a one word answer, it’s survival.
The answer to the question is B
After mining, to reclaim the land, the depression is filled with rocks then the top is filled with loosely graded soil. Introduction of early succession plants is important before big trees can grow. The early succession plants help in the breaking down of the rocks into soil hence making the topsoil deeper to support trees.