Question

a dna profile using 15 strs may show as many as ____ bands.
150
30
15
60

Explanation:

Humans are diploid, meaning each STR locus has two alleles (one from each parent). For 15 STRs, the maximum number of distinct alleles (and thus bands in a profile) is 15 × 2 = 30. This occurs when each STR locus is heterozygous (different alleles from each parent).

Answer:

B. 30