Question

a crime scene investigation reveals a small blood sample. the forensic team uses dna fingerprinting to identify the suspect. which statement best explains why dna fingerprinting is a reliable method for identification?

it detects the presence of certain genes that determine physical traits like eye color.

it analyzes specific regions of dna that vary greatly among individuals, making it highly unique.

it measures the number of chromosomes in a cell, which differs between individuals.

it compares the entire dna sequence of individuals, which is identical in all humans.

Explanation:

• Option 1: DNA fingerprinting isn't mainly about detecting genes for physical traits like eye color. It focuses on unique DNA regions, not just trait - determining genes.
• Option 2: DNA fingerprinting analyzes specific variable regions of DNA. These regions have high variability among individuals, making each person's DNA fingerprint unique (except identical twins), so this is a reliable way for identification.
• Option 3: The number of chromosomes in human cells is generally the same (46 in most cases) and doesn't differ between individuals in a way that's useful for identification.
• Option 4: The entire DNA sequence is not identical in all humans. There are variations (polymorphisms) that make each person's DNA unique, so this statement is incorrect.

Answer:

B. It analyzes specific regions of DNA that vary greatly among individuals, making it highly unique.