Q6 of 805 Page 1

Justify the need for signing of Montreal Protocol by the participating nations.

Montreal protocol is an international treaty designed to protect the ozone layer by reducing the production of numerous substances that are responsible for ozone depletion. It entered into force on 16 September 1989. The protocol was signed to curb the increasing ozone depletion by controlling the emission of ozone depleting substances (ODS). It is because of the agreement that stringent measures have been taken and the ozone hole over Antarctica has reduced in size.


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26

(a) Name the types of flowers produced by Viola (Pansy). How do theydiffer from each other?

(b) Describe the kind of pollination in one of the types of flowers that ensures seed-set production.


(c) Describe the process of pollination in Vallisneria.


OR


(a) Describe the technique that can help a healthy married woman who is unable to produce viable ova but wants to bear a child.


(b) Draw a labelled diagram of a human ovum.


(c) How is polyspermy prevented in humans?


 3

Write the role of histone protein in packaging of DNA in eukaryotes.

 8

Draw a sectional view of an apple and label the different parts of an ovary in it. Fruits develop from an ovary. Then why is apple referred to as a false fruit?

 10

Name a bioactive molecule, its source organism and the purpose for which it is given to organ transplant patients.