A.) sexual phenotypic traits
Answer:
O.
Explanation:
There are different types of soils and it is made up of different layers or horizon such as A, B, C, O, R and E. Together all the horizons forming soil profile. Each horizon containing different soil types.
O horizon: Known as top layer of the soil which contains layer of organic matter which is about two inches thick, and made up of humus such as decomposing leaves, dark-colored, carbon rich matter, twigs and microbial biomass which is mixed with small grained minerals for the formation of aggregate structures.
Evolution can be defined as the process of the change occurring in a population over a period of time through genetic variation. This genetic variation and the process of natural selection help a species to evolve by selecting the traits that helps it to better adapt to the environment. These genetic variations are inherited over time as the species continue to evolve.
Hence, the correct answer is 'change in population through genetic variation over time'.
