Global warming :An increase in the percentage of carbon dioxide, methane, nitrous oxide and chlorofluorocarbon traps the heat causing the temperature of the earth and its surroundings to rise. This is known as global warming.
Acid rain :When sulphur trioxide and nitrogen oxide present in the air mix with rainwater they form sulphuric acid and nitric acid respectively. Rainwater containing these acids is called acid rain.
Answer the question put against the following constituents of air : Carbon dioxide : “Although carbon dioxide plays no role in respiration, all life would come to an end if there is no carbon dioxide in air.” Support this statement with relevant facts.
Answer
Carbon dioxide is essential for photosynthesis by which green plants prepare their food. It minimises heat loss by radiation. Thus, it balances the temperature on earth.
Answer the question put against the following constituents of air : Oxygen : What is the percentage proportion of oxygen in air ? Why is oxygen called active air.
Answer
20.9%, oxygen is called active air because it supports life on earth. It is essential for the process of combustion.
Answer the question put against the following constituents of air: Nitrogen : Explain its significance for plants and animals.
Answer
Plants convert nitrogen into protein. It is an important constituent of proteins, which are necessary for the growth of animals, plants and human beings. Plants convert nitrogen into proteins.