Answer:
The correct answer is "9 cycles".
Explanation:
The minimum number of cycles necessary to replicate a fragment of DNA over 500 times is 9 cycles. In Polymerase Chain Reaction (PCR) method, the fragments of DNA are doubled in each cycle. This means that after "n" cycles, the total number of fragments is given by the equation 2^n. In this case, after 9 cycles a total of 512 DNA fragments will be obtained, because 2^9 is equal to 512.
Crossing over does helps in genetic diversity as it provides with new genes combinations. In crossing over, chromatids exchange genetic information during the meiosis. This mixing of genetic information provides the offspring with its own unique genetic makeup with some similarities with the parent’s genetic system. Crossing over is very beneficial in terms of giving the offspring more variability that helps in becoming more resistant to a disease and be a better version than parents.
I will go with A ....as radiation is out of question..... DNA sequence is same in all.......I don't think evolution is a mistake !
so A
Keystone species, they kinda hold the food webs together
Answer:
Differential reproduction leads to a change in allele frequencies over time. This occurs because of natural selection favoring "successful" individuals that produce more viable offspring.
The sickle-cell allele is maintained in populations exposed to malaria through balancing selection, since heterozygous individuals have protection against the disease.
