Hadean is the first eon of precambrian, and took place around 4.6 and 4.0 billion years ago.
Dominant' traits will actually disappear faster if they are disadvantageous.
Think about it: if everyone who has even a single copy of a particular allele is at a disadvantage (manifests the phenotype, in this case six fingers), then even single copies are selected against.
In the case of recessive traits, selection occurs only against homozygous carriers, who may be very rare if the allele itself is rare.
A concrete example would be something like Tay-Sachs disease. If the allele that causes this were dominant, every carrier would die before adulthood, and it would occur only as a very rare de novo mutation. But because it is recessive, it persists for now; heterozygous carriers have no disadvantage.
Meiosis sexual reproduction only occurs in the gametes, which do not contribute to the body's growth and repair, only reproduction.
Replication mitosis, however, produces diploid cells identical to the parent/mother cell, which aids in the body's growth and repair.
Not entire sure because I haven't taken human anatomy but I'd guess it would have to be the digestive enzymes breaking it down
