Answer: C

Explanation:

Rhizobium is a symbiotic bacterium living in the form of nodules in the roots of pulse crops which fixes atmospheric nitrogen and makes it available to the plants. Mainly Misorhizobium and CyanoRhizobium are such bacteria which have proved helpful in forming glands in the roots of pulse crops and in nitrogen fixation. Hence, statements 1 and 2 both are correct.

Answer: B

Explanation:

Blue-green algae: These are aquatic microorganisms. These organisms have the ability to fix nitrogen. But not all blue green algae are capable of nitrogen fixation. Hence, statement 1 is incorrect.

Only a few species can do this work. Some blue green algae are also found symbiotically with higher plants, such as Nostach and Anabaena, etc. These economically low cost bio-fertilizers are capable of providing desired benefits to crops through nitrogen fixation. Hence, statement 2 is correct.

Answer: B

Explanation:

Sun is the eternal source of energy on Earth. Coal, petroleum and natural gas are fossil fuels and are also non-renewable energy sources. It is extremely worrying that these energy sources are rapidly depleting to meet the needs of industry and transportation. Sunlight, wind, water, biomass, geothermal heat are some of the renewable resources of energy. Hence, statement 1 is incorrect.

Out of these, fossil fuels (coal, petroleum, natural gas, oil shale, bitumen, tar sands and heavy oil), hydro and nuclear power are conventional resources, whereas solar, bio, wind, ocean, hydrogen and geothermal energy are non-conventional or alternative energy resources. Hence, statement 2 is correct.

Answer: C

Explanation:

Electricity is produced from hydroelectric and coal-burning power plants in a similar manner. In both cases the power source is used to rotate the turbine. A coal-burning power plant uses steam to rotate turbine blades; Whereas a hydroelectric plant uses falling water to rotate a turbine. Hence, statement 1 is correct.

Hydroelectric plants, which are driven by water turbines, make indirect use of solar energy. Flowing and falling water, like rain from a cloud, falls on the turbine and rotates its blades. Even today, the energy of flowing water is used to transport wooden logs from inaccessible places in the hilly areas. Water mill has been used for grinding grains. During evaporation in the water cycle, a part of the solar energy is converted into potential energy of water molecules. Hence, statement 2 is correct.

These molecules rise up in the atmosphere and form clouds, due to which the potential energy of water molecules gets converted into kinetic energy during rain and snowfall. The kinetic energy of flowing water is used by hydropower plants to generate electricity on a large scale. The flow of rivers is stopped by building dams. Where water from the upper part of the dam is dropped through pipes onto the blades of turbines built near the base of the dam. Hence, statement 3 is correct.

Answer: C

Explanation:

Energy Village is a concept in which arrangements are made to meet all the energy needs of the rural area from locally available energy sources. Its objective is to make villages self-reliant in the field of energy. This not only fulfills the needs of domestic energy, lighting, irrigation, etc.; There are possibilities of using it as commercial energy also. Biogas plant for cooking in an ideal energy village; Solar batteries for television, radio etc.; A windmill operated by a biogas engine, which provides drinking water and irrigation, is expected. For this ambitious scheme, the Department of Non-Conventional Energy Sources has established 'Rural Renewable Energy System' RRES. Under this system, it has been used successfully in many villages and work on it is going on in many villages. Hence, all three statements are correct.