1. Trait B is likely to have arisen earlier because this trait has been replicating and existing in a higher percentage of the population as compared to trait A.

    Trait B is likely to have arisen earlier because this trait has been replicating and existing in a higher percentage of the population as compared to trait A.

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  2. The child is suffering from myopia. This defect can be corrected by using a concave lens of suitable focal length.

    The child is suffering from myopia. This defect
    can be corrected by using a concave lens of suitable focal length.

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  3. For a normal human eye, this distance is 25 cm. The far point of the eye is the maximum distance to which the eye can see the objects clearly. The far point of the normal human eye is infinity.

    For a normal human eye, this distance is 25 cm. The far point of the eye is the maximum distance to which the eye can see the objects clearly. The far point of the normal human eye is infinity.

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  4. The person is able to see nearby objects clearly, but he is unable to see objects beyond 1.2 m because the image formed in front of the retina. To correct this defect of vision, he must use a concave lens. The concave lens will bring the image back to the retina.

    The person is able to see nearby objects clearly, but he is unable to see objects beyond
    1.2 m because the image formed in front of the
    retina.
    To correct this defect of vision, he must use a concave lens. The concave lens will bring
    the image back to the retina.

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  5. When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases, and the distant objects are clearly visible to the eyes. To see the nearby objects clearly, the ciliary muscles contract making the eye lens thicker. Thus, the focal length of the eye lens decreases and theRead more

    When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length
    increases, and the distant objects are clearly visible to the eyes. To see the nearby objects
    clearly, the ciliary muscles contract making the eye lens thicker. Thus, the focal length of the
    eye lens decreases and the nearby objects become visible to the eyes. Hence, the human eye lens is able to adjust its focal length to view both distant and nearby objects on the retina.
    This ability is called the power of accommodation of the eyes.

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