The reproductive period is marked by characteristic events repeated almost every month in physiologically normal woman (28 days with minor variation) in the form of a menstrual flow
The menstrual cycle consists of 4 phases:
(i) Menstrual or Destructive phase 
(ii) Follicular or Proliferative Phase
(iii) Ovulatory Phase
(iv) Luteal or Secretory Phase 

(i) The main part of the ovule is the nucellus which is enclosed by two integuments leaving an opening called as micropyle.
(ii) The ovule is attached to the ovary wall by a stalk known as funiculus.
(iii) Chalaza is the basal part.
(iv) The embryo sac contains seven cells and eight nuclei located within the nucellus.
(v) Three cells at the micropylar end form the egg apparatus and the three cells at the chalaza end are the antipodal cells.
(vi) The remaining two nuclei are called polar nuclei found in the centre.
(vii) In the egg apparatus one is the egg cell (female gamete) and the remaining two cells are the synergids.

a) The first menstruation is called menarche. It occurs at the age of 11 to 13 years.
b) Napkin hygiene measures are:
(i) The sanitary pad and tampons should be wrapped properly and discarded because they can spread infections.
(ii) Sanitary pad or tampon should not be flushed down the toilet.
(iii) Napkin incinerators are to be used properly for disposal of used napkins.
c) Rahini's objection is correct.
(i) The advertisement gives some knowledge about the napkin.
(ii) How to use the napkin and what is the purpose of it.
(iii) The advertisement is answers some more questions.
(iv) It create the awareness among the females. So the object are correct.

(i) Before puberty and during development, the secretion of estrogen and progesterone are not secreted.
(ii) So it does not form ovary.
(iii) So menstrual does not take place before puberty and during pregnancy.

(i) Vegetative cell degenerates and the generative cell divides to form two sperms (or male gametes)
(ii) Tip of pollen tube bursts and the two sperms enter the embryo sac.
(iii) One sperm fuses with the egg (syngamy) and forms a diploid zygote.
(iv) The other sperm fuses with the secondary nucleus (Triple fusion) to form the primary endosperm nucleus which is triploid in nature.
(v) Since two types of fusion syngamy and triple fusion take place in an embryo sac the process is termed as double fertilization.
(vi) After triple fusion, primary endosperm nucleus develops into an endosperm.
(v) Endosperm provides food to the developing embryo.
(vi) The purpose of carrying two gametes is one is to form zygote another is to form endosperm to provide food to the developing embryo.

(i) Yes, it is necessary to take the blood reports for both boy and girl to ensure that he or she is free of any sexually transmitted diseases (STD) like syphilis, AIDS.
(ii) No, blood test report is necessary for both boys and girls living all over the world.

A small family is a happy family. If there are one or two children in a family, the parents can afford to give them good education, food, personal care and other facilities required for them to grow into healthy and happy individuals. Thus it is important for parents to plan a small family which will also build a healthy nation.

(a) Placenta.
(b) A pregnant woman should eat a balanced diet and take lot of fresh fruits and vegetables.
(i) She should be stress free.
(ii) She should not take any medicines without the advice of a doctor

(i) Pollen grains reach the right stigma and begin to germinate.
(ii) Pollen grain forms a small tube-like structure called pollen tube which emerges through the germ pore. The contents of the pollen grain move into the tube.
(iii) Pollen tube grows through the tissues of the stigma and style and finally the ovule through the micropyle.
(iv) Vegetative cell degenerates and the generative cell divides to form two sperms (or male gametes).
(v) Tip of pollen tube bursts and the two sperms enter the embryo sac
(vi) One sperm fuses with the egg (syngamy) and forms a diploid zygote.
(vii) The other sperm fuses with the secondary nucleus (Triple fusion) to form the primary endosperm nucleus which is triploid in nature.
(viii)Since two types of fusion syngamy and triple fusion take place in an embryo sac the process is termed as double fertilization.
(ix) After triple fusion, primary endosperm nucleus develops into an endosperm.
(x) Endosperm provides food to the developing embryo.
(xi) Later the synergids and antipodal cells degenerate.

Cross pollination takes place through the agency of animals, insects, wind and water.
Pollination by wind (Anemophily):
(i) The pollination with the help of wind is called anemophily.
(ii) The anemophilous flowers produce enormous amount of pollen grains.
(iii) The pollen grains are small, smooth, dry and light in weight.
(iv) The stigmas are comparatively large, protruding and sometimes hairy, to trap the pollen grains. E.g: Grasses and some cacti.
Pollination by insects (Entomophily):
(i) Pollination with the help of insects like honey bees, flies are called entomophily.
(ii) To attract insects these flowers are brightly coloured, have smell and nectar
(iii) The pollen grains are larger in size, the exine is pitted, spiny etc., so they can be adhered firmly on the sticky stigma. Approximately, 80% of the pollination done by the insects is carried by honey bees. 
Pollination by Water: The pollination with the help of water is called hydrophily. This takes place in aquatic plants.
(i) Pollen grains are produced in large numbers.
(ii) Pollen grains float on surface of water till they land on the stigma of female flowers. E.g:Hydrilla, Vallisneria. Pollination by Animals :
(i) When pollination takes place with the help of animals, it is called Zoophily.
(ii) Flowers of such plants attract animals by their bright color, size, scent etc. E.g: Sun bird pollinates flowers of Canna, Gladioli etc., Squirrels pollinate flowers of silk cotton tree.