Answer:
Because natural selection selects for it. Thus it persists.
Explanation:
You have to understand heterozygote advantage. Basically, it's where heterozygotes have an advantage over homozygotes. In the case of sickle cell disease, heterozygotes have an advantage, and natural selection favors whatever is advantageous. Thus, because heterozygotes each have one recessive sickle-cell allele, as natural selection favors the heterozygotes, the recessive sickle-cell allele persists and remains in the gene pool.
Answer:
B.
burning of fossil fuels
it increase the amount of carbon present in atmosphere.
Although earthquakes often occur before a volcanic eruption, they are not the cause. The earthquakes are the result of magma (molten rock) moving underground leading up to an eruption. A few volcanic eruptions are thought to have been triggered or initiated by earthquakes, but this is not the typical case.
Answer:
Glucagon signals the liver to start producing glucose.
Explanation:
Glucagon signals the liver to start producing glucose from the breakdown of amino acids through gluconeogenesis process. When the glucose level decreases in the body due to fasting or starvation, the pancreas release glucagon which provides signals to the liver to produce glucose form non carbohydrates substances present in our body. This production of glucose increases the concentration of glucose in the blood and the body used this glucose for the generation of energy molecules in the form of ATP.
