Consider the following statements about ‘Biochemical Oxygen Demand’ (BOD):
1. It is the amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water.
2. Highly polluted water have BOD value of less than 5 ppm.
Which of the statements given above is/are correct?
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Read the following statements carefully in the context of ‘particulate pollutants’?
1. Smoke particulates consist of gaseous or mixture of gaseous and liquid particles formed during combustion of organic matter.
2. Dust is composed of fine solid particles produced during crushing, grinding and attribution of solid materials.
3. Mists are produced by particles of spray liquids and by condensation of vapours in air.
4. Fumes are generally obtained by the condensation of vapours during sublimation, and boiling.
Which of the statements given above are correct?
Consider the following statements:
1. The aperture of the pupil of a human eye can be changed with the help of the ciliary muscles.
2. The curvature of human eye cannot be changed, because the lens of a human eye is fixed.
Which of the statements given above is/are correct?
The nearest and the farthest points up to which a normal human eye can see objects clearly are between:
The twinkling of a star occurs due to atmospheric refraction of starlight. This twinkling phenomenon occurs only in stars and not in planets, it is because of which of the following reasons?
Consider the following statements:
1. Methanol is a low carbon, hydrogen carrier fuel produced from high ash coal, CO2 from thermal power plants and natural gas.
2. ‘Methanol Economy’ programme has been launched with the objective of reducing India's oil import bill and greenhouse gas (GHG) emissions.
3. The Methanol Economy programme has been launched by the Ministry of Petroleum and Natural Gas.
Which of the statements given above is/are correct?
Consider the following statements:
1. Small intestine is the longest part of the human alimentary canal.
2. Carnivores have a longer small intestine than herbivores.
Which of the statements given above is/are correct?
According to Archimedes’ principle - When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it. Which among the following are based on the application of this principle?
1. Ships
2. Lactometer
3. Thermometer
Select the correct answer using the code given below:
In the context of ‘immunity’ in human body, which of the following statements is/are correct?
1. Skin on our body is an example of innate immunity.
2. Acquired immunity is characterised by memory.
3. Injecting the microbes deliberately during immunisation induce passive immunity.
Select the correct answer using the code given below.
Which among the following method(s) is/are used by pests to attack crops sown in the field?
1. They attack the root of the plant.
2. They bore into stem and fruits of the plant.
3. They suck water from various parts of the plant.
Select the correct answer using the code given below:
The most common nutrients causing eutrophication are: