Urea, ammonium sulphate, super phosphate are the examples of fertilisers.

Sprinkler system is more useful on an uneven land where sufficient water is not available. Perpendicular pipes, having rotating nozzles on top, are joined to the main pipeline at regular intervals. When water is allowed to flow through the main pipe under pressure with the help of a pump, it escapes from the rotating nozzles. It gets sprinkled on the crop as if it is raining. A sprinkler is very useful for sandy soil.

Ploughing is the process, which prepares the soil for the growth of a crop. It helps in loosening the soil, makes it well aerated, brings nutrient rich layer to the top and mixes nutrients evenly. It does not have anything to do with uniform distribution of water. 

Compost is a form of organic nutrient obtained by the decomposition of dead plants and animals, and thus it belongs to the category “manure”. Fertilisers refer to the inorganic salts being prepared in the factories. Pesticides and weedicides are the chemicals, which act against pests and weeds, respectively. 

Irrigation is done after adding manure and fertilisers, so that along with water, minerals and fertilisers are also absorbed by the soil.

Combine can do both harvesting and threshing.

Manual method refers to hand picking of the weeds. Chemical method refers to spray of weedicides to prevent the growth of weeds. Biological control method refers to the use of some insects or other organisms, which help in the destruction of weeds by feeding on them and thus is the correct option. 

Grains are stored in the sacs made of jute or metallic bins and are stored at places known as silos or granaries.

Paddy is a crop but grass is just a weed.

Farmers store grains in jute bags or metallic bins. Large scale storage of grains is done in silos and granaries.

Crop rotation is done to increase the fertility of the soil. 

Weeds may be a problem only during the growing stage of a crop, not after harvesting.

Manure is not prepared in factories. Fertilisers are prepared in factories.

Drip system, sprinkler system, etc. are modern methods of irrigation.

Gram is a rabi crop. It grows in a winter season. The rest of them are kharif crops.