The phenotype or genome of the individual organism. Remember, individuals are selected, populations evolve.
It acts on populations.
Indirectly, yes it does. But it can only act on genotypes through their phenotypes.
heritable
Yes it does. Without variance in the organisms genome, that gives variance to the phenotype, there would be nothing for natural selection to select from.
yes
I know of no government that acts, in any direct or significant way, on natural selection.
Yes, that would be called the Homologous structure, and that changes in natural selection.
no there is no genetic variation for natural selection to act upon
in need helpl asap
From the papers I am reading there may be mechanisms to insure only top quality sperm make it into the ejaculate.
Crossing-over increases the genetic variation within a population, which is required for natural selection to act upon.
The trait is the same for all organisms.