I. Very short answer questions:
1. Can you store pickles in plastic containers? Why?
2. What is carbonization?
3. Why is petroleum called fossil fuel?
4. If wheat is sown in the kharif season, what would happen discuss.
5. Give two disadvantages of using fertilizers excessively,
6. What is coal tar? Write its uses.
7. Write two advantages of judicious use of energy?
8. How is fire extinguished at airports and petrol pumps?
9. Differentiate between endangered and extinct species.
10. What are rock shelters? Where are they found?
11. Where are chromosomes found in a cell? State their function.
Answers
Answer:
1. Pickles should be stored in glass and not plastic containers as they have high salt and acid content and thus will react with the plastic. Such eatables should be kept in glass containers to avoid any chemical reaction.
2.Carbonization is the term for the conversion of an organic substance into carbon or a carbon-containing residue through pyrolysis or destructive distillation.
3. Over millions of years, heat and pressure from Earth's crust decomposed these organisms into one of the three main kinds of fuel: oil (also called petroleum), natural gas, or coal. These fuels are called fossil fuels, since they are formed from the remains of dead animals and plants.
4.If wheat is sown in the Kharif season (from June to October), then the whole crop might get destroyed because of many factors such as lack of optimum temperature, adaptability, availability of pests, etc. Kharif season includes the rainy season, which is not favourable for the growth of the wheat crop.
5. Disadvantages of using artificial fertilisers:
Crops grow better, but so do weeds. Therefore herbicide sprays are required too.
Better quality plants attract insects so pesticides may be needed.
Excess nitrogen from fertilisers gets into water supplies, causing fish to die.
Chemicals need to be used safely. In poorer countries in particular, farmers can
damage their health by applying fertilisers, pesticides and herbicides incorrectly.
Artificial fertilisers, applied without organic additions, do not improve soil structure.
6.Coal tar is used primarily for the production of refined chemicals and coal-tar products, such as creosote and coal-tar pitch. Certain preparations of coal tar have long been used to treat various skin conditions, such as eczema, psoriasis, and dandruff.
7. 1. The energy can be used sustainably that means the energy can be used for the future generation.
2. The cost of energy utilization will decrease, the will keep in balance of the economic status of the person.
8. At airports and petrol pumps fire is extinguished by using foam type fire extinguisher.
9.Extinct species are the organisms that have become extinct either in the wild or completely. An endangered species is a species of organisms facing a very high risk of extinction.
10. They are situated some 28 miles (45 km) south of Bhopal, in west-central Madhya Pradesh state. Discovered in 1957, the complex consists of some 700 shelters and is one of the largest repositories of prehistoric art in India. The shelters were designated a UNESCO World Heritage site in 2003.
11.Chromosomes are found in the nucleus of the cell.
They carry genes and help in inheritance or transfer of characters from parents to offspring.
Explanation:
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