Homozygous traits are either a combination of the same two dominant alleles or the same two recessive alleles. A hybrid trait is also known as a heterozygous trait, and is the pairing of a dominant and recessive allele.
because what they produce, it for animals to eat and because they are at the bottom of the ecosystem food chart. and also oxygen
They attach to the centromeres and pull apart new chromosomes to the opposite poles of the cell
The valves prevent the backward flow of blood.