read the paragraph.

wind turbines have become a hazard to birds and bats. many of these animals have flown into the turbines and have died. fish and wildlife agencies and conservation groups are concerned about the effect these machines have on these animals. the wind industry has sponsored research into the collisions. bird and bat behavior has been studied to minimize accidents at existing and proposed wind energy sites. careful site selection is key in reducing the accidents.

which sentence describes a problem-solution structure in the paragraph?

animals have been hurt by wind turbines, so the sites of wind farms have been carefully selected.

conservation groups are concerned about the dangers animals face with wind turbines.

birds and bats have flown into wind turbines and have died.

research has been conducted into the collisions of animals with the wind turbines.