Read the passage carefully and answer the following questions.

Environmental issues are the harmful effects of human activities on the environment. These include pollution, overpopulation, waste disposal, climate change, global warming, the greenhouse effect etc.

Climate change is a great concern in today's scenario. This problem has surfaced in the last few decades. Greenhouse gases are the major cause of climate change. Environmental changes have several destructive impacts such as the melting of glaciers, changes in seasons, epidemics, etc.

The burning of fossil fuels, emissions from automobiles and chlorofluorocarbon add to the greenhouse gases in the atmosphere. This has led to an increase in the earth's temperature causing environmental changes. This increase in temperature across the globe is known as global warming.

The ozone layer is a layer of concentrated ozone gas. It protects us from the sun's harmful ultraviolet rays. This very important layer is being destroyed by CFCs (Chlorofluorocarbons), which are used in industries and everyday life (e.g. aerosol cans).

The chlorine in these compounds destroys the ozone layer. The hole in the ozone layer leaves humans and wildlife exposed to harmful UV rays resulting in several skin diseases including cancer.

The introduction of harmful substances into rivers, oceans, lakes and ponds, which changes the physical, chemical or biological condition of the water is called pollution. The polluted water lacks oxygen and therefore the organisms die.

Air pollution is the result of emissions from industries, automobiles, and the increasing use of fossil fuels. The gaseous emissions have added to an increase in the temperature of the earth. Not only this, but it also increases the risk of disease among individuals.

Carbon dioxide is primarily called a green house gas because it:

Traps heat

The correct answer is option (1) – Traps heat

Carbon dioxide is primarily called a greenhouse gas because it has the tendency to trap the heat and does not let it escape. This causes an increase in the temperature and further global warming.