"A" bonds with "T", and "G" bonds with "C" (A-T) (G-C)
Primary succession is a method of fertilizing soil that was barren and had never supported plant life, for example soil left over by a moved glacier of lava.
The soil is first "normalized", using pioneer species such as lichens, algae and fungi.
After this, plants able to survive in less harsh conditions such as grasses.
Therefore, the fertility of soil during early years of primary succession does not increase much and it is a process that involves a long period of time.
I think the third is correct
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There are two types of self-pollination: in autogamy, pollen is transferred to the stigma of the same flower; in geitonogamy, pollen is transferred from the anther of one flower to the stigma of another flower on the same flowering plant, or from microsporangium to ovule within a single (monoecious) gymnosperm
