Olympiad Test: Natural Resources and Indian Heritage - Class 6 MCQ

Useful products that we obtain from nature are called natural resources. They are never harmful. Some resources are exhaustible e.g., petrol, coal, etc. While some resources are inexhaustible e.g., sunlight, air, etc. Resources we get from soil are mineral resources e.g., gold, coal while those we get from other than soil are non-mineral resources e.g., air and water.

Formation of soil is a slow and gradual process. Soil is formed by the breaking down of rocks by the action of wind, water, temperature and microorganisms. This is called weathering.

Humus is the dark coloured component of soil that is rich in organic matter. It makes soil fertile.

Lumber or timber is the wood used in construction work. Trees are the source of wood.

Pumice is a porous, light yet hard igneous rock. It is so light that it can float on water.

Black gold is another name of oil or petroleum. It is black when it comes out of ground and is worth a great deal of money.

Fossil fuels are the most important sources of energy for human beings. Coal and petroleum are kinds of sedimentary rock fossil fuels formed from the remains of plants and animals that lived million of years ago.

The relationship in the box pairs a sedimentary rock (sandstone) and an igneous rock (pumice) together. Similarly, conglomerate is a sedimentary rock and obsidian is an igneous rock.

Clayey soil holds large amounts of water. On drying, this water escapes and cracks develop. These cracks break plant roots making clayey soil not suitable for plant growth.

Water expands (increase in volume) upon freezing. This is due to the fact that upon freezing, water molecules crystallize  into an open hexagonal lattice form in which molecules enclose more space among themselves than in the liquid state. Thus, in the given case, volume of water increased when the water froze, forcing the stopper out of the bottle and forming the column of ice.