If earth is considered a " closed system " how does that shape the outcome of environmental problems? how does this relate to local regional environmental problems?

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?

If there are 350 trout found in 200 square feet of a pond measuring 1000 square feet what is the estimated trout population of the pond? a. 1350 b. 1550 c. 1750 d. 2000

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?