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.
Children should receive the first dose of MMR vaccine at age 12-15 months (i.e., on or after the first birthday). 1  In areas where risk for measles is high, initial vaccination with MMR vaccine is recommended for all children as soon as possible upon reaching the first birthday (i.e., at age 12 months).