Crossing over is the <span>mechanism of genetic variation results from the exchange of gene segments between non-sister chromatids.</span>
Answer:
(This could be opinion based, but ok.)
Explanation:
should:Pluto was known as a planet for 75 years. This means that most people already knew it as a planet, and would be extremely confused. All of the books about planets would be inaccurate and changed. Not all people can access brand new books, leading to inaccurate information.
shouldn't: The same reason that it was unclassified as a planet. It does not adhere to all of the rules of being a planet. It is not completely round and does not have a round orbit around the sun. Pluto does not have every requirement to be a real planet, and therefor, it would be incorrect to have it classified wrongly.
Answer: The correct answer for the given mechanisms influencing gene pool are the mechanisms of evolutionary change, which are described as follows-
1) Gene Flow
- It is described as the transfer of genes from one population to another population so that frequency of gene is increased.
-A zebra migrates to join a different herd of zebras.
2) Natural Selection
- A mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.
-Competition for sunlight leads to taller trees.
3) Mutation
- Permanent change in the nucleotide sequence of DNA ( genetic material) that could have harmful or useful consequences.
-The DNA of a snake changes to make its venom stronger.
4) Genetic Drift - It is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.
-A grassfire randomly sweeps through a population of buffalo and kills most of the animals.