Answer:
geographical isolation
Explanation:
Reproductive isolation is a process of evolution that ensures that members of different species are incapable of mating and when they do, such mating do not result into any offspring or leads to the production of invalid offspring.
There are two mechanisms of reproductive isolation:
- Pre-zygotic mechanisms prevents fertilization between two different species and these include habitat isolation, mating seasons, mechanical isolation, gamete isolation, geographical isolation and behavioral isolation.
- Post-zygotic isolation prevents the products of fertilization from becoming valid and this include hybrid inviability, hybrid sterility and hybrid breakdown.
<em>Geographical isolation involves the existence of geographical barriers between two populations such that there cannot be mating between the two. The two populations eventually evolve to become different species.</em>
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Ultraviolet is <span>responsible for causing sunburn </span>
Blood is considered<span> a </span>connective tissue<span> for two basic reasons: ( 1 ) embryologically, it has the same origin ( mesodermal ) as do the other </span>connective tissue types<span> and ( 2 )</span>blood<span> connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes .</span>
Add a picture so I can tell you
Hello. This question is incomplete. The full question is:
"You determine that you have only 3 copies left of an important DNA fragment, so you decide to amplify it. Using flanking primers, how many PCR cycles would you have to run to generate over one billion (10^9) copies of the fragment?
"
Answer:
Approximately 29 cycles of PCR would be required.
Explanation:
As you may already know, PCR is a technique used in molecular biology that allows part of a DNA molecule to be recycled into millions of copies.
PCR allows this replication to be done through cycles. Each PCR cycle lasts about 2 minutes and allows the DNA molecule to undergo the separation of the strands, the binding of the primers and the synthesis of new DNA strands through DNA polymerase. This cycle is usually repeated 32 times, but this number may change depending on the number of copies the researcher thinks is necessary.
In this case, if a researcher wants 10 ^ 9 copies of DNA, he must do the following calculation to find the number of PCR cycles needed:
32 ^ x = 10 ^ 9
x = 28.3 = approximately 29 cycles.
