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(D) 7 – 10 days

Sal trees grow in the Himalayan mountains.

Sexual reproduction help organisms to develop characters that would be help them to adapt better to their surroundings.

1. Preparing relevant slogans 

2. Organising rallies 

3. Awareness campaign by using electronic and print media

1. Spore formation is a method of asexual reproduction which occurs through microscopic reproductive units called spores. 

2. Most of the fungi like rhizopus, mucor etc., bacteria and non-flowering plants such as ferns and mosses reproduce by the method of spore formation.

3. In fungi like rhizopus spores are produced in some specialised structures called sporangia which bursts and spreads the spores into air. These spores when fall on food or soil under favourable conditions germinate and produce new plants. 

4. In non-flowering plants like fern, the leaves called sporophyll bears clusters of sporangia on their lower side. These sporangia produce the spores which produce the new plant when it falls on ground under favourable conditions.

1. Fertilisation that takes place outside the body of mother is called external fertilisation. This is most common in animals like fishes and amphibians. As the chance of fertilisation is controlled by nature it becomes necessary to give rise to vast number of eggs and sperms by these animals. 

2. Fertilisation that takes place inside the body of mother is called internal fertilisation. This is common in most of the land animals. As the chance of fertilisation is not controlled by the nature, these animals generally produce less number of eggs.

1. The uterus at the time of fertilization is beautifully adapted to receive the developing embryo, providing it with food and disposing of its wastes. 

2. A few days prior to this time, the uterus was small, its tissues were thin, and its supply of blood vessels was poor. 

3. When the fertilized egg or zygote is about to enter the uterus become much larger, its inner wall becomes thick, soft and moist with fluid, its blood supply is greatly increased and waiting for an embryonic occupant.

1. Release of the egg or ovum is called ovulation. 

2. The ova develop in tiny cellular structures in ovary called follicles, which at first look like cellular bubbles. 

3. As a follicle grows, it develops a cavity filled with fluid. 

4. Each follicle contains a single ovum. 

5. When an ovum is mature, the follicle ruptures at the surface of the ovary and the tiny ovum is flushed out. 

6. This release of ovum is called ovulation.

The release of ovum from graffian follicle is known as ovulation.

1. Perpetuation means continuation of life.

2. The perpetuation of life is based on the cell division. '

3. Both mitotic and meiotic divisions are very essential for perpetuation of life. 

4. In unicellular organisms, the mitotic cell divisions form the entire organisms. 

5. Mitotic division is essential for all types of asexual reproductions. 

6. In sexually reproducing organisms meiotic cell division helps in formation of gametes with haploid number of chromosomes which fuses to form diploid zygote during fertilization. 

7. Zygote further divides by mitosis again and grows into an embryo and then to offspring. 

8. Thus both mitotic and meiotic cell divisions play a key role in perpetuation of life. Without cell division, there is no perpetuation of life.

B) Continuation of life

(B) iii only

I shall ask the following questions to the doctor. 

1. What are the ways of transmission of HIV? 

2. How can we prevent the spread of HIV? 

3. What precautions should we take while doing transfusion of blood:

4. How does HIV transmit from mother to baby? 

5. Why should we use disposable syrenges?

1. Many organisms have the ability to give rise to new individual organisms from their body parts. 

2. Regeneration happens through mitosis and a particular type of tissue can give rise to its own kind only. 

3. In complex organisms, different tissues and organs have altogether different structures. 

4. Regenerating a different kind of tissue from another kind is not possible. 

5. Hence complex organisms are not able to give rise to new individuals through regeneration.

Regeneration: It is the capacity to regenerate the full body from a part of the body of several organisms. eg: Hydra, Planaria.

Chromatid: One copy of a duplicated chromosome is generally joined to the other copy by a centromere, for the process of nuclear division.

A pair of testis, Accessory glands and System of ducts.

Answer is (B) 2

B) Before detaching from the parent body, a bud may form another bud.

Answer is (C) Yeast

Budding: A bud develops as an outgrowth due to repeated cell division at the specific site which after developing into individuals detach from the body of the parent to become new individuals. eg: Hydra.

(B) Endosperm

The accessory glands present in male reproductive system are one prostrate gland . and two cow cowper glands.

(B) Condomes

(D) Graffian follicles

In our country, the legal age for marriage of boys is 21

a) Paramoecium : Paramoecium reproduces by splitting into two. (Transverse binary fission) 

b) Yeast: Yeast reproduces by Budding.

1. A bud develops as an outgrowth due to repeated cell division at specific site. 

2. These buds develop when fully mature, detach from the parent body and become new independent individuals.

Binary fission: Asexual reproduction method in which an organism split Into two equal halves. Eg: Paramoecium, bacteria.

In 1852 Robert Remak of Germany stated that animals can reproduce through binary fission of cells.

(B) 1 – b, 2 – a, 3 – c

The male reproductive system consists of a pair of the testis, accessory glands and a system of ducts.

The hormone testosterone regulates the development of the male reproductive organs.

1. In self pollinated plants anthers are usually present above the stigma. 

2. Pollen from the anthers drop on the stigma.

3. A process that takes place as the flowers close for the night, 

4. And sometimes occurs before they are completely developed and ready to open. 

5. At the time of pollination slightest movement of the flower’s petals stimulate the stamen to dislodge its pollen and transfer it to the near by stigma in pea plant. 

6. Pollination usually occurs before the flower is fully open.