Question

str analysis is a dna profiling technique that makes use of the fact that different people have different alleles for many genes in the genome. mostly the same genes in their genome different numbers of repeats of short dna sequences at certain sites in the genome. mostly different genes in their genome same numbers of repeats of short dna sequences at certain sites in the genome.

Explanation:

STR (Short Tandem Repeat) analysis is a DNA - profiling technique. The key idea is that at specific sites in the genome, different individuals have different numbers of repeats of short DNA sequences. This variation in the number of repeats (not alleles of genes in general, not mostly the same genes across the genome in a non - relevant way for STR analysis, not mostly different genes across the genome, and not the same number of repeats) is what is used in STR analysis.

Answer:

different numbers of repeats of short DNA sequences at certain sites in the genome.