1. Principal focus of a concave mirror is the point on its principal axis, where light rays coming parallel to the principal axis actually converge after reflection from the mirror.

    Principal focus of a concave mirror is the point on its principal axis, where light rays coming parallel to the principal axis actually converge after reflection from the mirror.

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  2. Variations are a continuous process and may not show an immediate advantage. However, under drastically changed environment, only those organisms may survive, where the variation gives them that advantage. Hence, i do not agree with this statement.

    Variations are a continuous process and may not show an immediate advantage. However, under drastically changed environment, only those organisms may survive, where the variation gives them that advantage. Hence, i do not agree with this statement.

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  3. Variations arise either because of errors in DNA copying, during asexual reproduction, which will be fewer; or because of fusion of gametes from two individuals in sexual reproduction. Since, in sexual reproduction, gametes from two different individuals with different genetic make up, are involvedRead more

    Variations arise either because of errors in DNA copying, during asexual reproduction, which will be fewer; or because of fusion of gametes from two individuals in sexual reproduction. Since, in sexual reproduction, gametes from two different individuals with different genetic make up, are involved so variations are much higher.

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  4. this was given by fool-proof experiment by Urey and miller 1953. They simulated the conditions present on primitive earth, in a flask. This contained reducing gases like methane, hydrogen sulphide, hydrogen, carbon etc. The temperature, just below 100 degree c was maintained and current was passed.Read more

    this was given by fool-proof experiment by Urey and miller 1953. They simulated the conditions present on primitive earth, in a flask. This contained reducing gases like methane, hydrogen sulphide, hydrogen, carbon etc. The temperature, just below 100 degree c was maintained and current was passed. At the end of a week, it was found that simple biomolecules were formed that included amino acids. This proved that in this manner, biomolecules would have come together and life originated.

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  5. Study of fossils helps us to know as to how character/features have evolved in different groups of organisms. We also can find out which organism evolved earlier, and from common ancestors, based on common features.

    Study of fossils helps us to know as to how character/features have evolved in different groups of organisms. We also can find out which organism evolved earlier, and from common ancestors, based on common features.

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