Correct Answer: (1) draining the swamps where mosquitoes breed

This has the least effect on the environment.

Incorrect Answers:

Spraying the swamps with chemical pesticides or oil could solve the mosquito infestation but may lead to other problems such as poisoning of other ecologically significant organisms.

Increasing the number of native fish might cause depletion of resources in the swamp.

Correct Answer: (3) human

Humans have the most diverse activities that cause harm to the ecosystems. Agriculture flourishes with the increase of human population that needs to be provided for. This lead to depletion of fish species due to overharvesting, spread of toxic compounds for controlling crop pest, and depletion of surface and groundwater by irrigation.

Correct Answer: (2) The air pollution problem in Baltimore is increase by the addition of pollution from other areas.

Incorrect Answers:

There are insufficient data to conclude statements 1, 3 and 4

Correct Answer: (1) global warming

One of the major causes of global warming is the rising carbon dioxide concentration. Much of the solar radiation that strikes the planet is reflected back to the space. Even if carbon dioxide and water vapor in the atmosphere are transparent to visible light, they intercept and absorb much of the reflected infrared radiation, rereflecting it back to the Earth's surface.  This process keeps some of the solar heat.

Incorrect Answers:

Deforestation refers to the overharvesting of trees in the forest by means of logging or burning.

Mineral depletion is the decrease in amount of available minerals especially those from the soil.

Industrialization is a modernization process wherein technological innovation occurs in an previously agrarian community. There is a development of large-scale energy and metallurgy production.

Initially, the water in the Rocky River is at 25 ^oC, and dissolved oxygen of 8.27 ppm. If they build a power plant which will release cold water (8 ^oC) into the river, the temperature will decrease. This also means that there will be an increase in the amount of dissolved oxygen, which is not the optimum amount for the survival of trout and black bass; and thus, might lead to a wiping out of these fishes' population in the Rocky River.