Tailings are dangerous because they can

a. release toxic elements into the groundwater or surface water

b. be very explosive

c. increase the chances of a volcanic eruption

d. decrease the amount of nonrenewable resources available

Its A= They can release toxic elements into the groundwater or surface water, hope this helped you out some bit :)

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