Sometimes, chemical damage to DNA can occur just before DNA replication begins, not giving the repair system enough time to correct the error before the DNA is duplicated. This gives rise to mutation. If the cytosine in the sequence TCAT is deaminated and not repaired, which of the following is the point mutation you would observe after this segment has undergone two rounds of DNA replication?
a. TTAT
b. TUAT
c. TGAT
d. TAAT

TTAT

Explanation:

Deamination is a reaction that causes mutations in DNA, with the release of ammonia. Deamination may convert cytosines into uracils. These mutations caused by deamination of cytosine are recognized by specific endonucleases that repair these modifications by replacement with cytosine

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.