Science [5 marks Questions]

1. Vasectomy: In males, a small portion of the sperm duct (Vasdeferens) is removed by surgical operation and both the cut ends are ligated properly. This prevents the sperms from coming out.
2. Tubectomy: In females, a small portion of the oviducts is removed by surgical operation and the cut ends are ligated. This prevents the ovum from entering into the oviducts.

1. The device X is condom.
2. Y represents sperms.
3. The device Z is copper-T.
4. The general name of these methods of birth control is called barrier method or IUCD (Intrauterine Contraceptive Device).
5. Using condoms (X) during sexual intercourse can protect a person from sexually transmitted disease.

1. Represents pollen grains. The process of transferring pollen grains from one flower to another flower of the similar plant by insects is known as cross pollination.
2. B represents the pollen tube.
3. C is the male gamete which moves down through the pollen tube (B).
4. D is the female gamete (or egg). The structure E represents the ovule.
5. F is the zygote.

1. A represents the vas deferens.
2. B represents sperms.
3. C represents the testes.
4. The cell D is the egg or ova.
5. The surgical method of birth control available to males is called vasectomy.

1. The worm X is Planaria.
2. The organism Y which posses the same characteristic as of X is Hydra.
3. The process in which a complete organism is formed from a lost body part of its parent is regeneration.
4. X and Y are multicellular organisms.
5. A dog cannot be produced from a lost body part like its tail, as this animal has a high degree of organisation in its body.

1. A is gonorrhoea and C is syphilis.
2. B is AIDS.
3. The virus D is Human Immunodeficiency Virus (HIV).
4. A, B and C can be caused by sexual contact with an infected person.
5. AIDS (B) does not have a definite cure as yet.

1. The alga X is likely to be Spirogyra.
2. The alga is green in colour.
3. This mode of forming new alga from the breaking-up of the parent alga is termed as fragmentation.
4. The splitting of Amoeba is termed as fission, which occurs only in unicellular organisms. The splitting of alga is termed as fragmentation, which occurs only in multicellular organisms.
5. Sea anemone reproduces in the same way as the alga X.

1. The organism X is yeast and organism Y is Hydra.
2. The process by which the organism X converts sugar into alcohol is fermentation.
3. Organism X is a fungus; hence, it belongs to the category of non-green plants.
4. Organism Y is a multicellular organism and comprises tentacles at one end.
5. Organism X is unicellular, and the organism Y is multicellular.

1. The fertilised egg cell E is also called the zygote.
2. The tissue T is the placenta.
3. The string-like structure S is the umbilical cord.
4. Oxygen and nutrients pass from the mother's blood to the embryo and carbon dioxide passes from the embryo to the mother's blood through the placenta (T).
5. When a baby is born, the umbilical cord is still attached to the baby. It is cut and tied to separate the baby from the mother.

• A is the ovum.
• B is sperm.
• C is the zygote.
• D is the uterus.
• E is the embryo.
• F is the foetus.

The person X is a female and Y is a male.
 

1. The shapeless lump of mass X is known as callus.
2. This method of producing new plants is known as tissue culture.
3. The jelly is called agar.
4. The chemicals used to stimulate the growth of plant cells and fasten the development of roots and shoots are called plant hormones.
5. Orchids and dahlia are two flowering plants that are propagated by this method.
6. The main advantage of this technique is that it is extremely fast, and the plantlets are obtained in a few weeks. Secondly, this method produces disease-free plantlets.
7. The other name of this technique is micropropagation.

1.  

1. The organ A is the ovary.
2. The gamete B is an egg.

2. The tube-like structure C is the oviduct or the fallopian tube.
3.  

1. D represents the testes.
2. The gamete E represents sperm.

4. The duct F is the sperm duct or the vas deferens.
5.  

1. The cell G is the zygote.
2. The ball of cells H is the embryo.
3. the organ I is the uterus.

6. ​​​​​​​

1. X represents female.
2. Y represents male.

The sexual reproduction in animals takes place in the following steps:

1. The male parent produces male gamete called sperms. The sperm is a small cell with a long tail (flagellum) for movement.
2. The female parent produces female gamete called ova which is much bigger cell than the sperm, having a lot of cytoplasm.
3. The sperm enters into the ovum and fuses with it to form a new cell called zygote and this process is called fertilisation.
4. The zygote then divides again and again to form a large number of cells and ultimately the zygote grows and develops to form a baby.

1. The common name of the organism is bread mould, and its scientific name is Rhizopus.
2. Spores of fungus are present in the air in their inactive form. When these spores get the favourable condition like a moist bread, they germinate and grow into new organisms.
3. The fine, thread-like projections on the surface of the bread are known as hyphae.
4. The knob-like structures are sporangium, which contain the spores.
5. This method of reproduction is known as spore formation.
6. Mucor fungus reproduces by the method of spore formation.
7. Ferns and mosses are two non-flowering plants which reproduce by this method.

1. A represents the carpel. The carpel is composed of the stigma, style and ovary.
2. The ovary contains gametes in the form of ovules.
3. B represents the stamen. The swollen tip of the stamen is the anther.
4. The anther has pollen grains.
5. The stamen (B) is a male part and the carpel (A) is a female part.

1. This method of propagating plants is known as layering.
2. To get propagated by this method, a plant should have soft horizontal branches.
3. Jasmine and China rose are the two plants that are propagated by this method for their flowers.
4. Guava and lemon are the two plants that are propagated by this method for their fruits.
5. Strawberry gets propagated naturally by this method by forming runners.

1. The plant X is Bryophyllum.
2. The entities, Y, present on the leaves of X are known as buds.
3. Other than X, Begonia can also be reproduced by its leaves.
4. Money plant can be propagated from its broken stem similar to plant X.
5. Buds are present in the dry stems of the old grass lying in the fields. These buds get activated after a spell of shower, and start producing new grasses.

1. Tuber is the general name of those underground stems like X.
2. Potato is an example of X.
3. The points Y present on X are known as buds.
4. No, it is not necessary to plant the entire stem X in the ground. This stem has many buds (Y) on it that form the vegetative organ of reproduction.
5. This method of reproduction is termed as vegetative propagation.
6. The main advantage of this method is that it is comparatively faster to growing plants from seeds.

Ovaries are the primary reproductive organs in females, which produce ovum or egg. Above the ovary lies the oviducts, or fallopian tubes, which are connected to the uterus. The eggs move into the oviduct from the ovaries, where it gets fertilised by a sperm. The fertilised ovum develops into a baby in the uterus. The uterus is connected to the vagina by the cervix. The vagina opens outside the body and receives sperms.

1. A represents immature follicles.
2. B represents the process of ovulation.
3. The time period x is 28 days.
4. The event C is pregnancy.
5. The time period y is the gestation period, i.e., 9 months.
6. D represents the process of menstruation.
7. The chemical substance E is the hormone oestrogen.

In humans, fertilisation is internal. Sperms are introduced in the vagina by the penis during copulation. The sperms move up through the cervix, enter the uterus and pass into the oviducts. In the oviducts, the egg gets fertilised by one of the sperms. Zygote is formed by the fusion of a sperm and an egg. This zygote divides multiple times to form a hollow ball of the cells called embryo.

Variation is useful for the survival of species even in adverse environmental conditions. This happens as follows: There may be some drastic changes like excessive heat or cold etc in the habitat of a species of organisms. If all the organisms of a population living in that habitat are exactly identical, then there is a danger that all of them may die and no one would survive under these conditions. This will eliminate the species from that habitat completely however, if some variations are present in some individual organisms to tolerate these drastic changes then there is a chance for them to survive and flourish even in adverse environment. Example: Certain bacteria living in temperate water – If the temperature of water increases too much due to global warming most of them will not be able to tolerate excessive heat and would die however, if there are bacteria with variation then there is a chance for them to survive.

1. This method of propagating plants or trees is known as grafting.
2. The segregated stem of tree X is termed as stock.
3. The segregated stem of tree Y that is devoid of roots is termed as scion.
4. The layer Z is called the cambium layer.
5. The cambium layer of both the stems should be joined, as they are responsible for the growth of a new tree.
6. Four trees which are propagated by this method are apple, pineapple, orange and grapes.
7. The main advantage of cultivating plants in this method is that the graft will have the most desirable features of both the parts, i.e. the stock and the scion.

1. The organism A is Leishmania, B is Plasmodium, C is Amoeba and D is Paramecium.
2. One body feature of organism A is that it has a whip-like structure called flagellum at one end.
3. Female Anopheles mosquito carries the organism B and transmits it from one person to another.
4.  

1. Organism A reproduces by binary fission.
2. Organism B reproduces by multiple fission.

5. Organisms C and D are found in ponds.

1. The pills A contain hormones.
2. The common name of pills A is oral pills.
3. The pills B contain spermicides.
4. The common name of pills B is vaginal pills.
5. The general name of these methods of birth control is called chemical method.

1. The process is termed as (i) menstruation scientifically and (ii) periods in everyday language.
2. The approximate age for a girl to undergo her first period is between 10 and 12 years. A human female usually attains puberty or sexual maturity at this stage.
3. This process is repeated after every 28 days and usually lasts for 3 to 5 days.
4. The onset of this process signifies sexual maturity in human females.
5. During pregnancy, this process stops temporarily but starts again eventually.
6. At the age of about 45–50, this process stops permanently.

1. The structure P is the oviduct.
2. The cell Q is the eggs or ovum.
3. The organ R is oviduct.
4. The reproductive cell S is sperm.
5. The surgical method of birth control available to females is tubectomy.

1. This method of propagating plant is known as cutting.
2. While removing a small part of the shoot from the parent plant using a knife, one has to be careful about the fact that the shoot has some buds on it.
3. Sugarcane and banana are those two plants which are propagated by this method, and are consumed as food.
4. Using this method, many new plants can be produced from one plant. This is one of the advantages of this method.
5. This is an asexual method of reproduction, as it involves only one parent and no gamete formation.
6. The genetically identical plants produced by this method are called clones.

The sexual reproduction in plants takes place in the following steps:

1. The male organ of flower called ‘stamen’ makes the male gametes of the flower. These male gametes are present in pollen grains.
2. The female organ of a flower called ‘carpel’ makes the female gametes present in the ovules and are called ova or egg.
3. The male gametes present in the pollen grains fertilises the female gametes or egg cells present in the ovules.
4. The fertilised egg cells grow within ovules and become seeds.
5. The seeds produce new plants on germination.

Oviduct (Fallopian tube).
Ovary.
Uterus (Womb).
Vagina.

1. Part D – (Vagina).
2. Part B – (Ovary).
3. Part A – Oviduct.
4. Part C – Uterus.

1. Since the ovary of female release one egg every month, therefore, the uterus also prepares every month to receive a fertilised egg. The inner lining of the uterus becomes soft and thick with lots of blood capillaries in it. This preparation is necessary as in case the egg is fertilised by the sperm, it helps to keep the egg and nourish it. If however, the egg is not fertilised, then the thick lining of the uterus is not required and the uterus lining breaks down and comes out through the vagina in the form of blood and mucous. This is called menstruation.
2. Menstruation cycle in females:

1. When a girl reaches puberty at the age of 10? 12 years, the sex hormones released it her blood cause some of the ova in the ovaries to become mature.
2. Usually one mature egg is released from the ovary into the oviduct once every 28 days. This is called ovulation.
3. Before ovulation, the inner lining of the uterus becomes thick and spongy, and full of blood capillaries, and prepares itself to receive the fertilised egg.
4. If the ovum does not get fertilised, then the thick and soft inner lining of the uterus is no longer needed and hence it breaks and the dead ovum comes out from vagina in the form of bleeding called menstruation.
5. Menstruation usually occurs 14 days after ovulation and usually lasts for 3 to 5 days.
6. After menstruation is over, the inner lining of the uterus starts building up again so that it becomes ready to receive the next ovum in case it gets fertilised.
7. If the ovum does not get fertilised even now, then the menstruation takes place again and this cycle goes on repeating.

Working of human male reproductive system: The human male reproductive system consists of:

1. Testes: Are the primary reproductive organs in males which are in pair. These are oval shaped organs which lie outside the abdominal cavity. It makes the male sex cells called sperms and produces male sex hormones called testosterone.
2. Scrotum: Is a muscular pouch which houses the testes. It is present outside the abdominal cavity and maintains a lower temperature than the normal body temperature.
3. Epididymis: The sperms formed in the testes goes into a coiled tube called epididymis which stores the sperms temporarily.
4. Vas Deferens (sperm duct): It is a long tube which carries the sperms from epididymis to another tube called urethra.
5. Seminal vesicles and prostrate gland: Both these glands are present along the path of vas deferens and add their secretions to sperms which allows them to transport easily.
6. Penis: It is an organ which pass?s the sperms from the man’s body into the vagina in the women’s body during mating.

	Column I		Column II
(i)	Plasmodium	(j)	Multiple fission
(ii)	Spirogyra	(g)	Fragmentation
(iii)	Jasmin	(f)	Layering
(iv)	Apple tree	(k)	Grafting
(v)	Bryophyllum	(b)	Leaves
(vi)	Potatoes	(h)	Tubers
(vii)	Rhizopus	(a)	Spore formation
(viii)	Hydra	(d)	Budding
(ix)	Planaria	(c)	Regeneration
(x)	Leishmania	(e)	Binary fission
(xi)	Sugar cane	(i)	Cutting
(xii)	Rose	(i)	Cutting