How can dna be used to solve a crime

If DNA is found at a crime scene it can help locate people that were at the crime scene. If the criminal has committed crimes before their DNA will already be in the police system. If not they can take samples from suspects and pinpoint who committed the crime.

Humans can affect weathering and erosion in several ways.  humans cause  increases in acid rain and pollution, which increase the amount of  weathering  agents in the air and water, and then on land.for an easy answer: 1) acid rain2) pollution