Test: Our environment - 1 - Class 3 MCQ

Pollution is the process of making land, water, air or other parts of the environment dirty and not safe or suitable to use. This can be done through the introduction of a contaminant into a natural environment, but the contaminant doesn't need to be tangible.

The substance which produces pollution is called as pollutants. Pollutant may be the man made like smoke and natural like forest fire.

There are different types of pollution: water pollution, air pollution, solid waste pollution and noise pollution. All of these can be found in urban areas. The main sources of pollution are household activities, factories, agriculture and transport.

Earth's atmosphere is composed of about 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases. Trace amounts of carbon dioxide, methane, water vapor, and neon are some of the other gases that make up the remaining 0.1 percent.

Air Pollution –The crackers contains many toxic gases and chemical compounds which activates after getting in touch with exposed air and start harming us. Example Nitrous oxide, which remains in air for long time if the area doesn’t get heavy rain or strong winds. 
Cigarette smoking causes environmental pollution by releasing toxic air pollutants into the atmosphere. The cigarette butts also litter the environment, and the toxic chemicals in the residues seep into soils and waterways, thereby causing soil and water pollution, respectively. 

Through a process called photosynthesis, leaves pull in carbon dioxide and water and use the energy of the sun to convert this into chemical compounds such as sugars that feed the tree. But as a by-product of that chemical reaction oxygen is produced and released by the tree.

Other activities, including cutting down trees, also emit greenhouse gases. The high concentration of these greenhouse gases in the atmosphere is responsible for increasing more heat on Earth, which leads to an increase in global temperature. Climate scientists believe that human activities are the main reason behind global warming.

Water pollution is the release of substances into bodies of water that makes water unsafe for human use and disrupts aquatic ecosystems. Water pollution can be caused by a plethora of different contaminants, including toxic waste, petroleum, and disease-causing microorganisms.

You need water to digest your food and get rid of waste. Water is needed for digestive juices, urine (pee), and poop. And you can bet that water is the main ingredient in perspiration, also called sweat. Besides being an important part of the fluids in your body, water is needed by each cell to work.

Whenever we hear very loud noise it cause irritation. Noise annoyance can result from interference with daily activities, feelings, thoughts, sleep, or rest, and may be accompanied by negative emotional responses, such as irritability, distress, exhaustion, a wish to escape the noise and other stress-related symptoms.