Class 9 General Science NCERT Based - 4 - Free MCQ Practice Test with solutions,

• Viral proteins are proteins generated by a virus. As viruses hijack much of their host's cellular machinery to support their life cycle, they encode very few of their own genes; viral proteins are therefore generally structural components, for the viral envelope and capsid.

• Non-structural proteins and regulatory or accessory proteins can also be viral proteins. Antiviral proteins are proteins that are induced by human or animal cells to interfere with viral replication.

• These proteins are isolated to inhibit the virus from replicating in a host's cells and stop it from spreading to other cells.

• Rabies is a viral disease that is spread through the animal bite such as the dog. It is caused by the infection of rabies virus.

• The infection caused from this leads to encephalomyelitis i.e the inflammation of the brain as well as the spinal cord.

• The transmission of the virus happens through the saliva and affects the CNS or Central nervous system. This virus belongs to the family called Rhabdoviridae.

• AIDS or Acquired Immune Deficiency Syndrome is a syndrome caused by the HIV virus.

• In this condition, a person’s immune system becomes too weak to fight off any kind of infection or disease. AIDS is usually the last stage of HIV infection; a stage where the body can no longer defend itself and thus spawns various diseases.

• Salmonella typhi is the bacterium responsible for this disease and humans are the only carriers.

• The first case of typhoid fever was reported in the United States in the early 1900’s. Overall, about 21 million people are infected with this disease annually, and about 200,000 cases are fatal.

• Congenital refers to a condition or disease which is present at birth. The condition can be inherited (genetic) or caused by environmental factors. Some maternal infections, such as HIV, can be passed onto the child and cause a congenital condition.

It develops resistance against pathogen attack.

A change in pressure of the water bodies

• Nitrogen fixation is the essential biological process and the initial stage of the nitrogen cycle. In this process, nitrogen in the atmosphere is converted into ammonia (another form of nitrogen) by certain bacterial species like Rhizobium, Azotobacter, etc. and by other natural phenomena.

• Plants are the main source of food. The nutrients obtained from plants are synthesized by plants using various elements which they obtain from the atmosphere as well as from the soil.

• This group of elements includes nitrogen as well. Plants obtain nitrogen from the soil through the process of protein synthesis. Unlike carbon dioxide and oxygen, atmospheric nitrogen cannot be obtained through the stomata of leaves.

• Because the concentration of nitrogen gas present in the atmosphere can not be directly used by plants and also the concentration of the usable form of nitrogen in the atmosphere is very less. There are certain bacteria and some natural phenomena which help in Nitrogen fixation.

These layers are:

• Troposphere

• Stratosphere

• Mesosphere

• Thermosphere

• Exosphere

Characteristics of Laterite Soil:
- Presence of iron oxides in the soil
- Formed by the erosion of rocks in areas of high temperature
- Soil appears red in colour
- Found in western and eastern ghats
- Soil is not very fertile
Explanation:
The characteristics mentioned above are indicative of laterite soil. Let's break down each characteristic and explain why it points to laterite soil:
1. Presence of iron oxides in the soil: Laterite soil is rich in iron oxides, which gives it a reddish color. This characteristic is consistent with laterite soil.
2. Formed by the erosion of rocks in areas of high temperature: Laterite soil is formed through the weathering and erosion of rocks in hot and humid tropical regions. This characteristic matches the formation process of laterite soil.
3. Soil appears red in colour: As mentioned earlier, the presence of iron oxides in laterite soil gives it a reddish color. This characteristic aligns with laterite soil.
4. Found in western and eastern ghats: Laterite soil is commonly found in the western and eastern ghats of India. This characteristic specifically points to laterite soil.
5. Soil is not very fertile: Laterite soil is known to be relatively infertile due to its high iron content and leaching of nutrients. This characteristic supports the identification of laterite soil.
Conclusion:
Based on the given characteristics, it can be concluded that the soil type described is laterite soil.

• Ozone is a poisonous gas and is thus only present in a thin layer in the stratosphere. lf all the oxygen is converted to ozone, the environment will become poisonous and kill all living forms. Ozone is O3, in its elemental form or even in its combined form it is highly toxic.

• Ozone can damage lungs and even low amounts of ozone can cause chest pain, coughing, shortness of breath and lung irritation.However at the stratospheric level, no life form exists and there ozone prevents us from the harmful U.V radiations of the sun.

(i).The use of a single farm for multiple purposes, as the growing of cash crops or the raising of livestock is called mixed farming.

(ii) Farming involving both the growing of crops and the keeping of livestock is called mixed farming.

(iii) A type of commercial agriculture concerned with the production of both crops and animals on one farm. Stock on a mixed farm used to be grazed on fallow land, but many modern mixed farms produce some, or all, of their fodder crops.

• Inland fisheries are any activity conducted to extract fish and other aquatic organisms from "inland waters". The term "inland waters" is used to refer to lakes, rivers, brooks, streams, ponds, inland canals, dams, and other land-locked (usually freshwater) waters (such as the Caspian Sea, Aral Sea, etc.).

• Biotechnology is being used to address problems in all areas of agricultural production and processing. This includes plant breeding to raise and stabilize yields; to improve resistance to pests, diseases and abiotic stresses such as drought and cold; and to enhance the nutritional content of foods.

• Biotechnology is being used to develop low-cost, disease-free planting materials for crops.