Answer:
The law of segregation is the Mendel’s laws or principles explain that traits are passed from parents to offspring individually instead of as pairs, groups or sets.This is a law or principle which states that during the formation of gametes, two copies of each heredity factors separate out so that the new offspring can get one factor of both the parents. This law was the first law in this direction.
I'm not sure but it might be C
The species was a keystone species.
Keystone species are the species that ''hold the ecosystem together''.
They have an important role in the trophic networks (food chains) and often they can even afflict changes in the abiotic part of the ecosystem (change the composition of soil, purify the water, lower the effect of the wind etc)
Therefore, when a keystone species is removed it affects greatly the whole ecosystem.
In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.
Hope this help