Explain the procedure for collecting a DNA sample.

The procedure for collecting a DNA sample is most accurately described by swabbing the inside of a cheek or collecting blood samples while following strict protocols to prevent contamination. This method is widely accepted in forensic practice as it allows for the efficient collection of cellular material that is rich in DNA.

When collecting a DNA sample via cheek swabbing, a sterile swab is used to gently scrape the inside of the mouth, where cheek cells can be collected. Blood samples are also a reliable source of DNA, as blood contains white blood cells that hold genetic information. It is critical to adhere to strict protocols during the collection process to avoid contamination, which could compromise the integrity of the sample. This includes using sterile tools, wearing gloves, and ensuring that the environment is free from contaminants.

Options that focus exclusively on hair follicles, urine samples, or nail clippings do not encompass the most reliable and widely-used methods for DNA collection. While they can provide DNA, they are less commonly utilized and may present challenges in terms of contamination or degradation of the sample. Thus, the preferred methods of cheek swabbing and blood collection are foundational to proper DNA evidence gathering in forensic procedures.