Answer:
A. It allows two populations to evolve separately.
Explanation:
Geographic isolation is theorized to have catalyzed the formation of new species. Let’s say groups A and B of a bird species get separated by something, and they can’t cross between to interbreed or exchange alleles.
We describe this as no gene flow, which is the opposite of choices C and D. Because of this, they may diverge if given enough time due to the difference in environmental pressures, because they’re now in different environments.
B is incorrect because it doesn’t apply.
Answer:
carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur
Forest biome: It gives us medicinal plants, woods for commercial purpose. Forests provides us rubber and fibers that is very important for the industries for making various products. They also contribute to perform ecological functions such as carbon storage, nutrient cycling, water and air purification. It also provides habitat to the wildlife.
Freshwater biome: We use fresh water for drinking water, irrigation, sanitation systems, and in industrial factories. Water used from groundwater, rivers and lakes is regained by rain and snowfall.
Marine biome: It serves huge amount of oxygen into the environment and absorbs the atmospheric carbon dioxide.
As a result of the activity of human there is a significant decrease in the number of trees. The products now used are synthetically made which were made up of natural fibers previously. The water source such as rivers, lakes, and ponds are polluted due to which many water borne diseases are increasing day by day. The accumulation of waste which are found in marine biome are reducing the number of flora present inside marine ecosystem.
Pepsinogen, an inactive zymogen, is secreted into gastric juice from both mucous cells and chief cells. Once secreted, pepsinogen is activated by stomach acid into the active protease pepsin, which is largely responsible for the stomach's ability to initiate digestion of proteins.
The right answer is B) crossing over.
Crossing-over is a genetic phenomenon that occurs during meiosis and contributes to genetic mixing during reproduction (genetic recombination).
At the end of prophase 1 (early metaphase 1) of meiosis, the homologous chromosomes (i.e. of the same pair) overlap thus forming characteristic features called "chromatid tetrads" and exchange fragments of chromatids. The result is the intra-chromosomal mixing of the alleles
