CBSE Solutions for Class 10 English

જવાબ : The two types of germ-cells present in human beings are sperm and ova. The sperm of human have either X or Y chromosome. The ova always carry X chromosome. The sperm is structurally long with a tail. The ova is round in structure.

જવાબ : Prostate glands and seminal vesicles add fluid in the vas deferens. This makes transportation of sperms easier and also provides nutrition to the sperms.

જવાબ : Advantages of vegetative propagation are:

1. Plants raised by vegetative propa-gation can bear fruits and flowers earlier.
2.  Plants produced are genetically similar.
   Banana and Rose can be raised by vegetative method.

જવાબ : DNA copies generated will be similar, but may not be identical to the original as some variations are so drastic that new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die. Therefore, there could be many other variations in the DNA copies that would not lead to such a drastic outcome. Thus, the surviving cells are similar but slightly different from each other. This tendency of variation during reproduction is the basis for evolution.

જવાબ : Rhizopus reproduces by spore formation. Conditions favourable for spore formation are:
(i) Cool place, (ii) Moist place and (iii) Dark place.

જવાબ :  Asexual reproduction is the process of producing new organism from a single parent without the involvement of sex cells. Fission and fragmentation are two different forms of asexual reproduction.

જવાબ : The period, when the rate of general body growth begins to slow down and reproductive tissues begin to mature, is called puberty.
Two changes observed in girls at the time of puberty are:
(i) The breast size begin to increase, (ii) Menstruation starts.

જવાબ : The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. This is a disc which is embedded in the uterine wall and transfers glucose and oxygen from the mother to the embryo.

જવાબ : Two advantages of practising vegetative reproduction in orange plants are:
(i) The oranges produced are similar in size and shape.
(ii) Many oranges do not produce viable seeds and hence, vegetative method is good alternative.

જવાબ : The sex chromosome of human male is XY. A sperm of human male carries either an X chromosome or one Y chromosome.
The sex chromosome of human female is XX and hence, the egg always carries the X chromosome.
If a sperm carrying X chromosome fertilises an egg which carries X chromosome, then the’ child born will be a girl. If a sperm carrying Y chromosome fertilises an egg which carries X chromosome, then the child born will be a boy.

જવાબ : (a) When a slice of bread is kept in moist dark place for a few days, spores of Rhizopus present in air settle on the bread to form new fungus plants of Rhizopus.
(b) The Rhizopus consists of fine thread-like projections called hyphae. It has a knob like structure which is involved in reproduction called sporangia, containing spores, that develop into new Rhizopus.

(c) Two advantages for organisms to reproduce themselves through spores are as follows:
(i) It is a faster mode of reproduc-tion.
(ii) Offsprings produced are identical.

જવાબ :

• Hydra reproduces by budding using the regenerative cells.
• A bud develops as an outgrowth in Hydra due to repeated cell division at one specific site.
•  When fully matures, the bud detaches itself from the parent body and develops into new indipendent individuals
  

જવાબ : DNA copying is an essential part of the process of reproduction because:
(i) DNA copying provides cellular apparatus in the daughter cells.
(ii) DNA in daughter cells will be able to control the functioning of daughter cells.
(iii)DNA copies will retain the traits.

જવાબ : Four modes of asexual reproduction are—Binary fission in Amoeba, Fragmentation in Spirogyra, Regeneration in Planaria and Budding in Hydra.

જવાબ :

જવાબ : (a)
(i) Implantation: The embedding
of a fertilised mammalian egg (embryo) into the inner thick wall of the uterus (womb) where it will continue its development is called implantation.
(ii) Placenta: It is a complex double-layered spongy vascular tissue in human female formed by the joint activity of maternal and foetal tissues in the wall of uterus that is meant for attachment, nourishment and waste disposal for the foetus.
(b) The average duration of human pregnancy is 40 weeks or 280 days.

જવાબ : Sexually Transmitted Diseases (STDs) are the diseases which are spread by sexual contact from an infected person to a healthy person. They are caused by various microorganisms that live in warm and moist environments of the vagina, urethra, anus and mouth.
The four sexually transmitted diseases are:
(i) Gonorrhoea
(ii) Syphilis
(iii) Trichomoniasis
(iv) AIDS (Acquired Immune Deficiency Syndrome).
AIDS damages the immune system of human body.

જવાબ : Reproduction is the process of producing new individuals of the same species by existing organisms of a species, z.e. parents. Its two types are: Asexual reproduction and Sexual reproduction.
Sexual reproduction confers new characteristics on the offspring due to variation in DNA copying.

જવાબ : The largest cell present in the human body is ovum.

જવાબ : Artificial methods of vegetative propagation like layering is used for growing jasmine plant.

જવાબ :  Artificial methods of vegetative propagation like cutting are used to grow rose plants.

જવાબ : The DNA in the cell nucleus is the information source of making proteins.
The two basic events in reproduction are:
(i) Creation of a DNA copy,
(ii) Additional cellular apparatus by the cell involved in the process.

જવાબ : Mode of reproduction used by
(a) Amoeba is Binary fission.
(b) Planaria is Regeneration.

જવાબ : (a) The role of seminal vesicles and the prostate gland are as follows:
(i) Seminal vesicles produce seminal plasma which is in the form of fluid makes the transport of sperms smooth.
(ii) Prostate gland secretes prostatic fluid that keeps the sperms alive and helps them to swim vigorously.
(b) Two functions performed by testis
in human beings are as follows:
(i) Formation of sperms takes place in testis.
(ii) They secrete the hormone testosterone which regulates the formation of sperms and brings changes in appearance of boys at the time of puberty.

જવાબ : It is because the chances of survival depend on the nature of variations and different individuals have different kinds of advantages.
For example, a bacteria that can withstand heat will survive better in a heat wave, i.e. the organisms that are fit in the competitive environment and with great variations will be able to survive and adapt. Thus, more offsprings and population with genetic variations will survive.

જવાબ : Reproduction is the process of producing new individuals of the same species
by existing organisms of a species, i.e. parents. The importance of DNA copying in reproduction are as follows:
(i) DNA copying is called DNA replication. In this process, one copy each of replicated DNA will be passed to daughter cells.
(ii) Variations may be introduced during DNA copying. This inbuilt tendency for variation during reproduction forms the basis of evolution.

જવાબ :  DNA copying is not perfectly accurate and the resultant errors are a source of variations in populations of organisms.

જવાબ :  Unisexual is the plant whose flowers contain either stamens or carpels but not both. Example: Papaya, Watermelon.
Bisexual is the plant whose flowers contain both stamens and carpels. Example: Hibiscus, Mustard.\ During fertilisation in plants, the following events take place:
(i) One of the male gamete fuses with the female gamete present in the embryo sac.
(ii) The other male gamete fuses with the two polar nuclei in the embryo sac.
The first fusion product gives rise to the zygote while the second one forms the endosperm.
The process of two fusions occurring in the embryo sac is called double fertilisation.

જવાબ : bacterial, viral

જવાબ : copper-T

જવાબ : ovules, fruit

જવાબ : fallopian tube

જવાબ : female

જવાબ : Embryo

જવાબ : placenta

જવાબ : cross pollination

જવાબ : thick walls

જવાબ : variation

જવાબ : Menarch

જવાબ : HIV-Human Immuno Virus

જવાબ : Uniparental/ Asexual reproduction
 

જવાબ : Vegetative propagation

જવાબ : Regeneration

જવાબ : fallopian

જવાબ : Vas deferens
 

જવાબ : Advantages of autogamy:

જવાબ : As a mother eats something the nutrient like glucose, proteins, fats, vitamins, etc. are absorbed into the mother’s blood by the small intestine. The nutrients flow to the placenta, and then transferred to the baby’s bloodstream through the umbilical cord. The baby’s waste products (like CO2) are disposed of in the mother’s blood stream as well. In the placenta, the mothers blood flows into a network of blood Vessels and capillaries. Molecules in the mother’s blood like glucose, proteins, fats, oxygen etc. flow out of the mother’s blood supply and are absorbed into another network of blood vessels and capillaries containing the baby’s blood supply. The baby’s blood then flows through the umbilical cord back to the baby. It is the complete process of baby’s nutrition inside womb.

જવાબ : There are two main procedures of completing fertilization in flowering plants, which are:
(i) Pollination
(ii) Fertilisation

જવાબ : A week after the sperm fertilizes the egg, the fertilized egg (zygote) undergo development and become a multicelled blastocyst. The blastocyst fix itself into the lining of the uterus, called the endometrium. The hormone estrogen causes the endometrium to become thick and rich with blood. Progesterone and other hormone released by the ovaries, keeps the endometrium thick with blood so that the blastocyst can absorb nutrients from uterus. This process is called implantation

જવાબ : In unicellular organisms, reproduction occurs by the division of the entire cell. The modes of reproduction in unicellular organisms can be fission, budding etc. whereas in multi cellular organisms, specialised reproductive organs are present. Therefore, they can be reproduced by complex reproductive methods such as vegetative propagation, spore formation etc. In more complex multicellular organisms such as human beings and plants, the mode of reproduction is sexual reproduction.

જવાબ : Since the ovary releases one egg every month, the uterus also prepares itself every month to receive a fertilised egg. Thus its lining becomes thick and spongy. This would be required for nourishing the embryo if fertilisation had taken place. Now, however, this lining is not needed any longer. So the lining slowly breaks and comes out through the vagina as blood and mucous. This cycle takes place roughly every month and is known a menstruation. It usually lasts for about two to eight days.

જવાબ : Advantages of vegetative propagation:

• Used in methods such as layering or grafting, to grow many plants like sugarcane, roses or grapes for agricultural purposes.
• Plants raised can bear more flowers and fruits in comparison to plants produced from seeds.
• Plants such as banana, orange, rose and jasmine which have lost the capacity to produce seeds can be propagated.
• All plants produced by vegetative propagation are genetically similar enough to the parent plant.

જવાબ : If a population of reproducing organisms were suited to particular niche and if the niche were drastically altered, the population could be wiped out. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.

જવાબ : Sexually transmitted diseases are infectious diseases transmitted during sexual contact. Various agents like bacteria and virus cause these diseases. For example, Gonorrhoea, syphilis, genital herpes, chlamydiasis, genital warts, trichomoniasis, hepatitis-B and HIV-AIDS are sexually transmitted diseases.

• Avoid sex with unknown partners/multiple partners,
• Always use condoms during coitus.
• Use of mechanical barrier like condom prevents transmission of infection

જવાબ :

• The energy needed for survival of the organisms is obtained by them from life processes such as nutrition and respiration.
• Reproduction needs a lot of energy.
• Genetic material is transferred from one generation to the next as a result of reproduction through DNA copying.
• DNA copying takes place with high constancy and considerable variations, that is, advantages to the species for stability in the changing environment.

જવાબ :

• Sperm enters through the vaginal passage during sexual intercourse and moves upwards.
• Egg released from the ovary reaches the fallopian tube (oviduct).
• Sperm encounters egg in the oviduct and fertilisation takes place. Fallopian tube (oviduct) is the site of fertilisation.
• An egg is released once every month by the ovary as usually one ovum (egg) is released by an ovary during each cycle.

જવાબ : Reproduction is the process by which an organism produces its young ones for perpetuation of its race. Some organisms have the ability to form new organisms from the pieces of its body which has been cut into different pieces. This process by which new organisms develop from the parts of an organism is called regeneration. Planaria and Hydra have the ability of regeneration.

જવાબ : The egg gets fertilised in the oviduct. The fertilised egg, the zygote gets implanted in the lining of the uterus and starts dividing. The uterus prepares itself every month to receive and nurture the growing embryo. The lining thickens and is richly supplied with blood to nourish the growing embryo.
The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. The development of the child inside the mother’s body takes approximately nine months. On completion of 9 months, the child is born as a result of rhythmic contractions of the muscles in the uterus.
If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood and mucous.

જવાબ : (a) Fragmentation: Multicellular organisms with simple body organisation such as filamentous algae-Spirogyra breaks up into two or more small pieces or fragments upon maturation. These fragments grow into new individuals.

(b) Regeneration: It is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts.

•  Small cut or broken parts of the organism body grow or regenerate into separate individuals.
•  Planaria can be cut into any number of pieces and each piece grows into a complete organism.
• Regeneration is carried out by specialised cells which proliferate and make large number of cells thus, undergoing changes to become various cell types and tissues.

The changes taking place in an organised sequence is development.

જવાબ : (i) Barrier Method: In this method, physical devices such as condoms, diaphragm and cervical caps are used. These devices prevent the entry of sperm in the female genital tract during copulation, thus acting ‘ as a barrier between them.
(ii) Hormonal Imbalance Method: In
this method, specific drugs are used by females, which are of two types: oral pills and vaginal pills.
Oral pills contain hormones which stop the ovaries from releasing ovum into the fallopian tube. These pills are also called oral contraceptives (OCs) which act by changing the hormonal balance of the body so that eggs are not released and fertilisation cannot occur. The use of Intrauterine Contraceptive Devices (IUCDs) prevents implantation in the uterus. This device is copper-T placed safely inside the uterus by a doctor or nurse.
(iii) Surgical Method: In this method, a small portion of vas deferens in male and the fallopian tube in ‘ female is surgically removed or tied. It is called vasectomy in males and tubectomy in females. In this case, if the vas deferens in male is blocked, sperm transfer will be prevented and if the fallopian tube in the female is blocked, the egg will not be able to reach the uterus, thus fertilisation will not take place.

જવાબ : (a) Four reasons for adopting contra¬ceptive methods are:
(i) To increase the gap between, two children.
(ii)To prevent unwanted preg¬nancy.
(iii)To prevent transmission of STDs.
(iv)To control population growth. (b) If a woman is using a copper-T,
it will not help in protecting her from sexually transmitted diseases. Copper-T prevents only implantation in the uterus.

જવાબ : HIV stands for Human Immunodeficiency Virus.
Yes, AIDS is an infectious disease.
Four modes of spreading AIDS are as follows:
(i) By having sexual contact with an infected person.
(ii) By the transfusion of blood from an infected person.
(iii) Through infected needles used for injection.
(iv) Through the placenta from the mother to child during pregnancy.

જવાબ : (a) Role of placenta in the development of human embryo: A special tissue develops between the uterine wall and the embryo (foetus) called placenta, where exchange of nutrients, glucose and oxygen takes place. The developing embryo will also generate waste substances which can be removed by transferring them into the mother’s blood through the placenta. The development of the child inside the mother’s blood takes approximately nine months.
(b) Sexually transmitted diseases (STDs) transmitted by bacteria are:
(i) Gonorrhoea (ii) Syphilis
STDs transmitted by virus:
(i) AIDS (ii) Genital warts
The most effective contraceptive which prevents the spread of these diseases is by the use of mechanical barriers such as physical devices like condoms.

જવાબ :

જવાબ :

જવાબ : In vegetative propagation, new plants are obtained from the parts of old plants like stems, roots and leaves, without the help of any reproductive organ.
There are two ways of vegetative propagation:
(a) Natural Vegetative Propagation, and
(b) Artificial Vegetative Propagation.
Natural vegetative propagation by leaves: The fleshy leaves of Bryophyllum bear adventitious buds in the notches along the leaf margin.
Grafting: In this method of reproduction, two plants of closely related varieties are joined together so that they live as one plant.

• The portion of a plant that is grafted on the other plant is called scion, and the plant in which grafting is performed is called the stock.
• This method is applied to improve variety of fruits like mango, apple, peas, citrus and guava.
  advantages of vegetative propagation are:

જવાબ : The full form of DNA is deoxyribonucleic acid. It is the genetic material found in the chromosomes, which are present in the nucleus of a cell.
Role of DNA in the process of repro¬duction of the cell:
 
DNA plays an important role in the reproduction of a cell. The reproducing cell produces an identical copy of DNA through some cellular mechanism. Since the newly formed copy of DNA lacks an organised cellular structure, the cell gets divided to provide cell cover to the newly formed DNA. Thus, two daughter cells are formed from the single cell as a result of the copying of DNA.

જવાબ : (i) Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants than growing plants from their seeds.
(ii) Better quality of plants can be maintained by this method.
(iii) It results in propagation of those plants which do not produce viable seeds or produce seeds with prolonged period of dormancy.
(iv) The plants generated from vegetative means are more uniform and genetically similar to the parent stock.

જવાબ : Regeneration is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts. More complex organisms cannot give rise to new individuals through regeneration because:
(i) their body is highly complicated.
(ii) there are specific organs to do specific functions.
(iii) there is a labour division in the body of complex organisms.
(iv) regeneration is carried out by specialised cells which are not present in complex organisms.

જવાબ : (i) Fertilisation is defined as the fusion of a male gamete (sperm) with a female gamete (an ovum or egg) to form a zygote during sexual reproduction.

(ii) The site of fertilisation in human beings is in the fallopian tube of female reproductive system.

જવાબ :

(i) (C)
(ii) (A)
(iii) (D)
(iv) (B)

જવાબ :

(i) (C)
(ii) (E)
(iii) (D)
(iv) (A)
(v) (B)

જવાબ :