Class 8 Chapter 1 MCQ

Explanation
Cow dung is a manure because it is organic matter that is derived from the waste products of cows. Manure is used as a fertilizer to improve soil fertility and provide essential nutrients for plant growth. Cow dung is rich in nitrogen, phosphorus, and potassium, which are essential nutrients for plants. It also helps in improving soil structure and water retention capacity. Therefore, cow dung is a natural and commonly used manure in agriculture.

Explanation
Rhizobium is a nitrogen-fixing bacteria. It forms a symbiotic relationship with leguminous plants, such as peas and beans, by colonizing their roots and converting atmospheric nitrogen into a form that the plants can use for growth. This process helps in enriching the soil with nitrogen, which is an essential nutrient for plant growth. Blue-green algae also have the ability to fix nitrogen, but in this case, Rhizobium is the correct answer as it specifically refers to a type of bacteria. Pencillium, on the other hand, is a type of fungus and does not have the ability to fix nitrogen.

Explanation
After ploughing, the soil is broken up into smaller pieces called crumbs. These crumbs are formed when the plough turns over the soil, breaking it into smaller clumps. These clumps then break down further into crumbs, which are important for soil structure. Crumbs allow for better aeration and water infiltration, as well as providing a loose and friable texture that is beneficial for plant root growth. Therefore, the correct answer is "Crumbs".

Explanation
Khurpi is a gardening tool that is specifically designed for weeding. It has a small, sharp blade that is ideal for removing weeds from the soil without disturbing the surrounding plants. Unlike ploughing, which involves turning over the soil, or irrigation, which involves watering the plants, weeding is the process of removing unwanted plants or weeds from the garden. Therefore, the correct answer is weeding.

Explanation
Zinc is not an essential element (nutrient) for plants. While nitrogen and potassium are important nutrients for plant growth, zinc is not required in large quantities for plants to thrive. Although zinc can be beneficial for plants in trace amounts, it is not considered an essential nutrient for their survival. Therefore, zinc is the correct answer as it is not an essential element for plants.

Explanation
Neem leaves are commonly used for the storage of grains due to their insect-repellent properties. Neem contains natural compounds that act as a deterrent to pests and insects, helping to prevent infestation and damage to stored grains. The leaves are often placed in grain storage containers or bags to protect the grains from pests and maintain their quality for a longer period of time. Amla and Ebony leaves do not possess the same insect-repellent properties as Neem, making Neem the correct answer.

Explanation
Threshing is the correct answer because it refers to the process of separating the grains from the stalk. It involves beating or shaking the stalks to loosen the grains, allowing them to fall off. Weeding is the process of removing unwanted plants or weeds from a field, which is not related to removing grains from the stalk. Winnowing, on the other hand, is the process of separating the grains from the chaff or husk by using wind or air currents. While winnowing is also a step in grain processing, it is not specifically focused on removing grains from the stalk.

Explanation
The correct answer is October to March. This is because the Rabi season in India is associated with the winter months when crops like wheat, barley, and mustard are sown. These crops require cool weather and less rainfall, which are typically found during the months of October to March. Therefore, this period is considered the Rabi season for agricultural activities in India.

Explanation
Drip irrigation is the best method for reducing water wastage because it delivers water directly to the roots of the plants in small, controlled amounts. This ensures that water is used efficiently and minimizes evaporation and runoff. Additionally, drip irrigation systems can be automated and adjusted to deliver the precise amount of water needed by each plant, further reducing wastage.

Explanation
The correct answer is "Food Corporation of India." FCI is an acronym for Food Corporation of India, which is a government organization responsible for ensuring food security in the country. It plays a crucial role in procurement, storage, and distribution of food grains across India. The organization also helps in stabilizing market prices and providing food grains to the poor at subsidized rates.