The building block of DNA is called the nucleotide, which is composed of a nitrogenous base (adenine, guanine, cytosine, or thymine), a five-carbon sugar (deoxyribose in DNA), â¦ and one to three phosphate groups. + 16 others found this useful.
Special cases of minimum ages and intervals. Two childhood vaccines require a bit more explanation regarding scheduling: â¢. MMR at age 1 year â Many statesâ school and childcare regulations specify that the minimum age for receipt of MMR vaccine be âon or after the first birthday,â with no allowance for a grace period.
The second dose of MMR may be given as early as 4 weeks after the first dose, and be counted as a valid dose if both doses were given after the first birthday. The second dose is not a booster, but rather it is intended to produce immunity in the small number of people who fail to respond to the first dose.