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With reference to the uses of ‘concave mirrors’, read the following statements carefully:
1. They are commonly used in vehicles headlights to get powerful parallel beams of light.
2. They are often used as shaving mirrors to see a larger image of the face.
3. They are fitted on the sides of the vehicle to have a wider field of view.
4. Large concave mirrors are used to concentrate sunlight to produce heat in solar furnaces.
Which of the statements given above is/are correct?
Which of the following is NOT an example of ‘Autoimmune Disease’?
Consider the following statements:
1. Cold-blooded animals do not have the capacity to regulate their body temperature.
2. Amphibians are cold-blooded animals and reptiles are warm-blooded animals.
Which of the statements given above is/are correct?
The parasitic nutritive strategy, by which some organisms derive nutrition from plants or animals without killing them, is used by which of the following organisms?
1. Cuscuta (amar-bel)
2. Ticks
3. Bread moulds
4. Tape-worms
Select the correct answer using the code given below.
Consider the following statements:
1. The motion of the moon around the earth is due to the centrifugal force.
2. The moon rotates around its axis due to the gravitational pull of the earth.
Which of the statement(s) given above is/are NOT correct?
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?
Fertilizers are commercially produced plant nutrients. In this context, consider the following statements:
1. Fertilizers get washed away due to excessive irrigation.
2. Micro-organisms in the soil are harmed by the continuous use of fertilizers.
3. Fertilizers supply nitrogen, phosphorus and sodium to the soil.
Select the correct answer using the code given below:
The presence of certain minerals is essential in water, however, if found in excess they can be harmful to our body. In this context, which of the following statements are correct?
1. Deficiency of fluoride in drinking water causes diseases such as tooth decay.
2. Excessive sulphate in drinking water causes laxative effect.
3. Excess lead in drinking water can cause disease such as ‘blue baby’ syndrome.
Select the correct answer using the code given below.
Some countries now use alcohol as an additive in petrol. In context of this, consider the following statements:
1. Addition of alcohol increases the burning efficiency of petrol and reduces knocking.
2. Petrol added with small quantities of alcohol becomes more stable and doesn’t become too hot in warm areas or too cold in freezing temperatures.
3. Alcohol is a cleaner fuel which gives rise to only carbon dioxide and water on burning in sufficient oxygen.
Which of the statements given above is the correct reason for using alcohol as an additive in petrol?
With reference to organic farming practices prevalent in India, consider the following statements:
1.