Updated By SaraNextGen

On April 21, 2024, 11:35 AM

Question 8:

Describe the ‘Greenhouse Effect’ in your own words.

Answer:

Greenhouse effect may lead to global warming, i.e., an overall increase in the average temperature of the Earth. Greenhouse effect is caused by greenhouse gases. Examples of greenhouse gases include carbon dioxide, methane, and water vapour. When solar radiations reach the Earth, some of these radiations are absorbed by earth and then released back to the atmosphere. Greenhouse gases present in the atmosphere trap these radiations and do not allow heat to leave. This helps in keeping our planet warm and thus, helps in human survival. However, an indiscriminate increase in the amount of greenhouse gases can lead to excessive increase in the Earth’s temperature leading to global warming.

Question 9:

Prepare a brief speech on global warming. You have to deliver the speech in your class.

Answer:

Global warming is an increase in the average temperature of the Earth’s surface. It occurs as a result of an increased concentration of greenhouse gases in the atmosphere. The greenhouse gases include carbon dioxide, methane, and water vapour. These gases trap solar radiations released back by the Earth. This helps in keeping our planet warm and thus, helps in human survival. However, an increase in the amount of greenhouse gases can lead to an increase in the Earth’s temperature leading to global warming.

Question 10:

Describe the threat to the beauty of the Taj Mahal.

Answer:

Acid rain is a major threat to the beauty of the Taj Mahal. When acid rains fall on the monument (that is completely made of marble), they react with marble to form a powder-like substance that is then washed away by the rain. This phenomenon is known as marble cancer. Also, the soot particles emitted from the Mathura oil refinery located near Agra is leading to the yellowing of the marble.

Question 11:

Why does the increased level of nutrients in the water affect the survival of aquatic organisms?

Answer:

An increase in the level of nutrients in a water body leads to an excessive increase in the population of algae in the water body. When these algae die, they serve as food for decomposers. A lot of oxygen is utilised in this process, consequently leading to a decrease in the level of oxygen dissolved in the water body. This in turn causes fishes and other aquatic organisms to die.