Answer: 1.An increase in air pollution. : Encourage the use of public transport.
2. A decrease in the number of trees.: Plant new trees and protect existing trees.
3. The loss of a bird habitat.: Providing nesting boxes.
4. An endangered aquatic species.: Regulate recreational activities such as boating and fishing.
Explanation:
1. The air pollution increases due to the discharge of partially combusted gases released from vehicles like carbon dioxide, carbon monoxide and others. These gases pollute the air. Thus, the use of vehicles should be minimized. Thus people should use public transport to reduce pollution.
2. The trees may reduce in number due to clear cutting, deforestation and because of other reasons. The population of trees in a region can be restored by growing plants.
3. The decrease in bird population may be because of habitat loss, pollution and climatic changes. The population of birds can be restored by providing them with boxes to stay as nest.
4. An endangered species is one which is left with limited population. An endangered aquatic species population can be managed by regulating the recreational activities as human beings may directly or indirectly affect them by throwing garbage to water bodies, oil spill and by other ways.