1. Describe natural resources with reference to the following three types.

(a) Mineral resources

(b) Forest resources

(c) Ocean resources

(a) Mineral resources

Ans: These resources are found in the earth’s crust and taken out of the mines. Some of them, like gold, silver, platinum, and bismuth, are found in their free states, while others, like iron, aluminum, and mica, are found in a mixed state called ores. The ores are separated and purified to get metals and non-metals. Besides metals, there are minerals like diamond, ruby, emerald, jade, zircon, etc. that are used as gems. Coal, petroleum, and natural gas are also minerals that are used as fuels. Thus, transportation and the production of electricity depend on mineral resources.

(b) Forest resources

Ans: An extensive area of land covered by a variety of plants is called a forest. A forest is a natural habitat for plants, animals, and microbes. About 30% of the total land area of the world is covered by forests. Forests perform certain specific protective and productive functions. They are:

(i) To reduce the velocity of water flowing over the land.

(ii) to prevent soil erosion.

(iii) To help the percolation of water into the ground.

(iv) To control floods.

(v) To reduce the rate of evaporation.

(vi) To protect wildlife.

(vii) To maintain the balance of atmospheric gases

Thus, forests help mangroves and maintain the quality of the environment.

(c) Ocean resources

Ans: Oceans can provide large amounts of energy; sea waves at high and low tide, as well as ocean currents, are used to generate electricity. At the bottom of the sea and beneath the seabed, there are reserves of a variety of natural resources; the resources available from seas and oceans are referred to as ocean resources. 

2. Write answers to the following questions in your own words.

(a) What is meant by fossil fuel ? What are their types ?

Ans: The fuels that are made from dead plants and animals that were buried millions of years ago and subjected to extreme pressure and temperature in the earth’s crust due to geological processes are called fossil fuels. There are three types of fossil fuels: heat, cool air, and natural gas.

(b) Make a list of the components we obtain from mineral oil.

Ans: Crude mineral oil is a mixture of many hydrocarbon compounds. Compounds are obtained from mineral oil, aviation, petrol, gasoline, diesel, kerosene, naphtha, lubricant oil, and tar.

(c) What do we get from forests ?

Ans: Forests give us wood for the construction of houses, furniture, farming implements, and household articles. We obtain cellulose, fibres, paper, rubber, gum, and aromatic substances. We also get fruits, bulbs, roots, sealing wax, cutech, and dyes.

(d) What are the items included in ocean resources? What are their uses ?

Ans: Oceans have two types of resources:

A) The non-living resources of minerals and fossil fuels:

(i) The mineral resources include thorium and uranium and deposits of magnesium, potassium, iodine, sodium, and sulphate from salt.

(ii) The fossil fuel resources include crude oil and natural gas.

(iii) Thorium and uranium are used for the production of atomic energy and electricity.

(iv) Oil and natural gas are used in industries and motor vehicles.

B) The living or biological resource:

(i) Fish, dried shrimp, Bombay duck powder, shells, shark, codfish, and sea cucumbers are the living resources.

(ii) Fish provide protein food, fish liver oil gives Vitamin A and D, dried trash fish powder is used as poultry feed, shells are used as decorative articles, and sea cucumbers are used for treating cancer and tumors.

(e) Why should we prevent the wastage of fuel used for vehicles ?

Ans: Petrol and diesel used in vehicles are fossil fuels made by geological processes in the earth’s crust over millions of years. Their reserves are limited and may exhaust in the years to come. Upon combustion in the vehicle engine, the fuels give off exhaust gases that are harmful and cause air pollution. Therefore, we should prevent the wastage of fuel used for vehicles.

(f) Why is the diversity of plants and animals in the forests declining?

Ans:

(i) Diversity in plants: Due to the increasing human population, more land is required. The forests are cleared and cut to make land for dwellings, farming, and industries. In farming, useful grains and vegetables used as food are grown. In forests, a few varieties used for manufacturing goods are planted. Such particles are reducing the diversity of plants in forests.

(ii) Diversity in animals: On account of hunting and preaching, animal populations are declining, and the reduced diversity of plants discourages a variety of wildlife from taking shelter and having food.

(g) Write the names of five minerals and the useful substances obtained from them.

Ans: The five minerals are iron, magnesium, bauxite, copper, and mica. The useful substances obtained from them are as follows:

(i) Iron: Iron is used to make metals like iron and steel. These are used for making heavy machinery, railroad tracks, farming implements, and articles such as needles, pins, etc.

(ii) Magnesium: Magnesium occurs in the form of various compounds such as carbonate, silicate, and oxide. These are used in preparation for medicines, electrical appliances, and also for giving a pink tint to glasses.

(iii) Bauxite: Bauxite is the most important, containing 55% aluminum. Aluminum, which is a good conductor of electricity, is used to make electricity wires. Since the density of aluminium is low, it is used in aircraft and other vehicles.

(iv) Copper: Copper, being a very good conductor of electricity, is used to make electric wires. It is also used in sodas, telephones, vehicles, statues, and for making kitchen utensils.

(v) Mica: Mica is used in ayurvedic medicines, dyes, electric machines, and equipment.

(h) Name the two important stages in the process of obtaining metals from ores?

Ans: The two important stages in the process of obtaining metals from ores are extraction and purification.

3. What steps are taken for protection and conservation of natural resources?

Ans: Natural resources are essential for meeting our needs, but because some reserves are limited, there is a risk that excessive use will result in their early deposition. We must keep a lid on the use of natural resources to maintain them.

4. Complete the flow chart.