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.

(i) The spermatozoan consists of head, a middle piece and tail.
(ii) The sperm head is elongated and formed by the condensation of nucleus.
(iii) The anterior portion has a cap like structure called acrosome.
(iv) It contains hyaluronidase, an enzyme that helps the sperm to enter the ovum during fertilization.
(v) A short neck connects the head and middle piece which comprises the centrioles.
(vi) The middle piece contains the mitochondria which provides energy for the movement of tail.
(vii) It brings about sperm motility which is essential for fertilization.

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.