Correct Answer – Option 2 – environmental carrying capacity

Decreasing completion may lead to an increase in frog population. Hence, option 1 is incorrect.

Excessive dissolved oxygen will help in the growth of water borne plants, providing more food for frogs.

This should lead to an increase in frog population. Hence, option 3 is incorrect.

The depth of water is not related to the population of the frogs. Hence, option 4 is incorrect.

Hence, the only reason why the frog population in a pond remains constant would be the carrying capacity of the environment. Hence, option 2 is the correct answer.

Correct Answer – Option 3 – industrialization has increased the amount of carbon dioxide in the air

Increase in carbon dioxide leads to the green house effect leading to the overall increase in temperature at Earth’s surface.

Destruction of decomposers does not cause an increase in temperature. Hence, option 1 is incorrect.

Trees consume carbon dioxide to release oxygen. Hence, deforestation will lead to an increase in the level of oxygen. So, option 2 is incorrect.

Plants – crops again consume carbon dioxide to generate oxygen. And oxygen in the atmosphere does not lead to depletion of ozone layer. Hence, option 4 is incorrect.

Correct Answer – Option 1 – Human actions are a threat to equilibrium in ecosystems.

The diagram above represents modifications of ecosystem by humans through the use of technology, consumption and population growth disrupting the equilibrium in ecosystems.

Hence, the options 2,3 and 4 are incorrect.

Correct Answer – Option 3 – Organisms in this food web are interdependent.

Only when organisms in a food web are interdependent the population, growth, or any character influencing one set of organisms will affect the other organisms which are interdependent.

In a food web both producers and consumers are important. Hence, option 1 is incorrect.

Both producers and consumers are needed to support the food web. Hence, option 2 is incorrect.

Due to various environmental, biotic and abiotic factors populations in a food web cannot be constant. Hence, Option 4 is incorrect.

Correct Answer – Option 2 – Temperature and amount of available water

Abiotic components are the nonliving components of an ecosystem. Chemical and geological factors, such as rocks and minerals, physical factors such as temperature and weather are referred to as abiotic factors.

Biodiversity is not a nonliving factor hence option 1 is incorrect.

Producers and decomposers in a forest ecosystem are living organisms. Hence, option 3 is incorrect.

Heterotrophs are living or biotic components of the forest ecosystem. Hence, option 4 is incorrect

Animals in the abyssal zone cannot survive the upper ocean zones due to the difference in water pressure. Their bodies are not be able to tolerate the low pressure of the upper ocean zones. Some deep-sea animals have collapsed lungs to make their body heavier than water, which makes sinking deeper easier. Some fishes located in the abyssal zone have developed lung-like swim bladders to manage their buoyancy. When they move up the water column, they secrete gas into the bladder by inflating it (What is "it'?). They move down by reabsorbing gas into their blood. The bladder does not collapse at depth because the pressure of the gas inside the bladder is equal to the pressure outside it. Thus, when the external pressure suddenly drops, the bladder will swell terribly.

Problem: increased ultraviolet radiation

This can be caused by the accumulation of chlorofluorocarbons, chemicals used for refrigeration, as propellants in aerosol cans, and in certain manufacturing services. When the breakdown products from the said chemicals reach the stratosphere, chlorine reacts with ozone, reducing it to molecular oxygen. The following reactions free up the chlorine, allowing it to react with other ozone molecules in catalytic chain reaction. The ozone located in the stratosphere absorbs the UV radiation, thus preventing much of it from contracting organisms.

Humans can be severely affected by the increased ultraviolet radiation. It can increase lethal and nonlethal types of skin cancer and cataracts.

One of the initiatives that have been taken by governments is the banning of the use of chlorofluorocarbons to lessen the impact of this problem.

Problem: global warming

Global warming is caused by carbon dioxide emissions and the greenhouse effect. When carbon dioxide accumulates in the atmosphere, much of the solar radiation that strikes the planet is reflected back towards the space. Since carbon dioxide and water vapor in the atmosphere absorb the infrared radiation, light is rereflected back to the earth. Thus, solar heat is retained contributing to the warming of the earth's temperature.

The rate of global warming has dramatically increased over the years. This contributed to the melting of glaciers in the temperate areas of the earth. Thus, glacial animals, such as the deer mouse, beaver and bald eagle, are threatened by global warming.

One of the ways to prevent or delay global warming is to decrease the use of organic fuels like coal, natural gas, gasoline, and wood. In 1992, leaders of the industrialized countries have signed a treaty that provides a framework for stabilizing carbon dioxide emissions.