Answer:
Natural selection by directional selection, was the driving force of evolution at work. The purple flowers parents were able to withstand the selective pressure and therefore emerged from completions with other flowers from previous generation, thus their dominance follow directional selection. This was the trait inherited by their offspring, the dominant purple
The gene pool of purple flower will be large; because of dominance in expression with each successive generation in both homozygote and heterozygote state, and therefore higher frequency of expression compared to the white flowers.
The frequency of allele depends on the rate expression of the allele in the population. Thus, the dominant purple flowers have high frequency of expression compared to the recessive white flowers which can only express itself in homozygote recessive state
Explanation:
Keystone species are animals that help manage other animal species by controlling population numbers and biodiversity within an ecosystem. The impacts of keystone species are usually greater than their numbers.
owls can be a great benefit to places where rodent populations are high. Dense urban areas often suffer from an abundance of rats and mice spreading disease, and rural agricultural communities have their crops consumed and soil eroded from burrowing voles and field mice. Without owls, and other top predators, rodent populations could explode and exacerbate the effects they produce.
Of the annual global total of fixed nitrogen, human activities account for roughly 45%.
Nitrogen fixation is the global amount of nitrogen that gets assimilated by any living organism into another organic compound. The organic compound can be ammonia or nitrogen ions.
Of the total global annual nitrogen fixation, humans account for a great amount. The current estimation is that humans cause 45% of the nitrogen fixation annually. The leading causes of this high rate are the burning of fossil fuels and increased agricultural fertilizer use.
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Answer:
When blood glucose level rises beyond the threshold levels, the pancreas secrets hormones insulin. The latter ensures entry of glucose into the cells through Glut transporters for cellular utilization, therefore reducing the blood levels., and promotes storage as glycogen in the liver and muscles.
How ever if the glucose levels drops below the set point, an hormone glucagon is also produce by the pancreas to cause the liver o withdrawal and breakdown glucose storage as glycogen back to glucose thus raising the blood glucose level back to the normal levels.
This is an example of negative feedback mechanism, because the increase in the input levels (blood glucose levels) brings about a counter mechanisms (insulin secretions)as output , to reduce the elevated levels by promoting entry into the cells,, thus bringing the levels to threshold levels.
Thus insulin is acting in a negative feedback mechanism to control blood glucose levels
Explanation:
