They all have diverse plant life with the occasion of animals sometimes
The difference between a dominant trait and a recessive trait is that the dominant trait must have one copy of each from two different parent
Example: Brown Hair=H
Light hair=h
Hh is dominant because this is of a copy of each from two parents
A recessive trait must have two same copies coming from the same two parents
Example: HH
Chromatids are only called as chromatids when they are sister chromatids, meaning that when chromosome have two double stranded DNA attached together, each of the double stranded DNA is a sister chromatid, and while the whole thing (the two sister chromatids that are attached together) is called a chromosome.
So after the DNA has been replicated, the chromosome consist of 2 sister chromatids, attached to each other at their centromere.
Overall, sister chromatid is one of the two double stranded DNA in a replicated chromosome, and chromosome is the whole "X" shape that we see. For example, in humans, after the S phase of interphase in the cell cycle, we have 46 chromosomes, with 92 chromatids, since each chromosome is an "X" shape, by having two sister chromatids.
Hope this helps!
Because all living things are made of carbon in one way or another and we use nitrogen and water naturally.