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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Consider the following statements:
1. A person with myopia can see nearby objects clearly but cannot see distant objects distinctly.
2. In a myopic eye, the image of a distant object is formed behind the retina and not at the retina itself.
3. The defect of myopia can be corrected by using a concave lens of suitable power.
Which of the statements given above is/are correct?
Consider the following statements about ‘rainbow’:
1. It is caused by dispersion of sunlight by tiny water droplets present in the atmosphere.
2. A rainbow is always formed in a direction opposite to that of the Sun.
Which of the statements given above is/are correct?
In the question given below, there are two statements marked as Assertion (A) and Reason (R). Read the statements given below carefully:
Assertion (A): The Sun at the sunrise or the sunset appears red whereas at noon, the Sun appears white.
Reason (R): Light from the Sun near the horizon passes through larger distance in the earth’s atmosphere than the light from the Sun overhead.
Choose the correct answer using the codes given below:
Consider the following statements:
1. Exchange of gases in plants occurs not only across the surface of leaves but also across the surface of stems and roots.
2. Plant close its pores known as the Stomata, when they do not need carbon dioxide for photosynthesis.
3. Guard cells present in plants are responsible for controlling the movement of water in them.
Which of the statements given above is/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?
Consider the following statements about the ‘properties of ethanol’:
1. Ethanol is insoluble in water.
2. Consumption of small quantities of dilute ethanol causes drunkenness.
3. Ethanol can be blended with diesel.
4. Ethanol is used as a solvent in many medicines.
Which of the statements given above are correct?
Consider the following statements about ‘Acid Rain’:
1. Oxides of sulphur and nitrogen are major contributors to acid rain.
2. Acid rain is good for agriculture as it provides nitrogen for the growth of plants.
3. When acid rain flows into the river, it increases the pH level of river water.
Which of the statements given above is/are correct?
Which among the following are the characteristic features of birds?
1. They are cold-blooded animals.
2. They lay eggs.
3. Two forelimbs are modified for flight.
4. They breathe through lungs.
Select the correct answer using the code given below:
Consider the following statements:
1. The ‘danger’ signal lights are red in colour as the red is least scattered by fog or smoke.
2. The sky appears dark to passengers flying at very high altitudes because of scattering of light.
Which of the statements given above is/are correct?
In context of ‘Scrub Typhus’, which of the statements given below is/are correct?
1. It is a disease caused by a bacterium and it spreads to people through bites of infected chiggers.
2. Antibiotics are most effective form of medicine to cure this disease.
3. Recently, a special vaccine has been developed for its prevention by the Department of Biotechnology.
Select the correct answer using codes given below: