How do Mendel’s experiments show that
Inheritance of two traits is independent of each other?
Mendel’s law of independent assortment states that when two pairs of traits are taken into consideration in a cross (dihybrid), one pair of character for a particular trait segregates independently of the other pair of character for a different trait. For example: In a dihybrid cross between two plants having round yellow (RRYY) and wrinkled green seeds (rryy) two traits are considered the colour of seed and shape of the seed. In this four types of gametes (RY, Ry, rY, ry) are produced. Each of these segregates independent of each other, each having a frequency of 25% of the total gametes produced. Thus the characters for the colour of the seed segregate independently from the characters of the shape of the seed.
Due to a gradual weakening of ciliary muscles and diminishing flexibility of the eye lens a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve the vision. Explain the structure and function of such a lens.
You have been selected to talk on “ozone layer and its protection” in the school assembly on ‘Environment Day.’
(a) Why should ozone layer be protected to save the environment?
(b) List any two ways that you would stress in your talk to bring in awareness amongst your fellow friends that would also help in the protection of ozone layer as well as the environment.
Name the organ that produces sperms as well as secretes a hormone in human males. Name the hormone it secretes and writes its functions.
A concave mirror produces three times magnified image on a screen. If the object is placed 20 cm in front of the mirror, how far is the screen from the object?
Why do the component colours of incident white light split into a spectrum while passing through a glass prism, explain?
