<span>It is usually the + strand and the - strand. It can be quite a bit more complicated.</span>
Answer: Natural selection is one of the forces of evolution and the enviroment where the species lives is the selection agent. For example, suppose a mosquitoes population in a environment free from insecticides, in this environment there's a high frequency of non-resistant mosquitoes because the environment is not exerting any pressure on the resistence trait. But when the environment changes and we use a insecticide upon the mosquitoes population, the populations changes because the non-resistant ones die but those resistant survive and beggin to reproduce more effectively. That's natural selection, differences in survival and reproduction between individuals with different phenotypes (traits) and this differences depend of environmental changes.
Answer: The genes have a codominant pattern of inheritance because the heterozygous forms both traits equally.
Explanation:
The study of human interaction with the natural world over time is environmental history, emphasizing the active role that nature plays in influencing human affairs and vice versa. ... The first, nature itself and its change over time, includes human physical impact on the land, water, atmosphere, and biosphere of the Earth.