Oocasionally, DNA evidence is thrown out of court due to the sample being contaminated.

What are some possible ways DNA samples from blood can be contaminated?

Answer: sneezing or coughing over the evidence, direct sunlight on transport an storage

Explanation:

DNA evidence is contaminated when DNA from an outside source (exogenous DNA) gets mixed with DNA relevant to the case. It can happen in a variety of ways, from someone sneezing or coughing over the evidence,