CBSE Solutions for Class 10 English

જવાબ : Evolution of reproductive isolation among once interbreeding population.

જવાબ : Formation of new species due to gradual change over a long period of time.

જવાબ : Whether a child inherits X chromosome or Y chromosome from father determines the sex of the child.

જવાબ : It refers to the transmission of characters or traits from the parent to their offspring.

જવાબ : In snail, sex is determined by environmental factors such as temperature.

જવાબ : Ammonite, trilobite, knightia and Rajasaurus.

જવાબ : J.R.S. Haldane.

જવાબ : Life originated in the sea water.

જવાબ : Men- Homo sapiens Garden pea- Pisum sativum

જવાબ : All plants in Fj generation will bear violet flowers.

જવાબ : Some genes are dominant and others are recessive. Tallness is a dominant trait and hence the progeny is always tall when crossed with a short plant.

જવાબ : The cross between two individuals with one pair of contrasting characters is called monohybrid cross.

જવાબ : Because cutting of tail is an acquired trait and is not inherited.

જવાબ : It is because of the variations which take place during DNA copying.

જવાબ : Deoxyribonucleic Acid (DNA) is a molecule which carry the hereditary characters or traits in a coded form from one generation to the next in all the organisms.

જવાબ : The change in the frequency of certain genes in a population over generations.

જવાબ : Gregor Johann Mendel is the father of genetics.

જવાબ : Genes are located on DNA present in chromosomes.

જવાબ : Gene.

જવાબ : Genetics

જવાબ : Gene is the unit of inheritance. It is the part of a chromosome which controls the appearance of a set of hereditary characters.

જવાબ : (i) Colours of eye
(ii) Height

જવાબ : Variation is defined as the differences in the characters or traits among the individuals of a species.

જવાબ : All the variations do not have equal chances of survival as some variations might not be beneficial and would ultimately be eliminated.

જવાબ : Because human being reproduce sexually and variation are more in sexually reproducing organisms.

જવાબ : Archaeopteryx

જવાબ : speciation

જવાબ : girl

જવાબ : Charles Darwin

જવાબ : two

જવાબ : recessive

જવાબ : analogous

જવાબ : Heredity

જવાબ : one

જવાબ : Darwin

જવાબ : genes

જવાબ : Recessive

જવાબ : Genotype

જવાબ : pair

જવાબ : acquired

જવાબ : J.B.S Haldane

જવાબ : True

જવાબ : True

જવાબ : Speciation

જવાબ : Africa

જવાબ : common

જવાબ : Broccoli, cauliflower

જવાબ : analogies

જવાબ : closely

જવાબ : genetic drift

જવાબ : genetically

જવાબ : chromosomes

જવાબ : natural

જવાબ : Genetically organisms are of types

જવાબ : (I) if any natural calamity occurs and kills these small number of surviving tigers, they can become extinct resulting in the loss of some genes forever.
(ii) Small number will lead to little recombination and, therefore, lesser variations. These both are very important for giving better survival chances to the species.
(iii) Less number of species means lesser extent of diversity and lesser number of traits which reduces the chances of adaptability with respect to the change in the environment.

જવાબ : During sexual reproduction there is ‘crossing over’ of chromosomes, that gives rise to variations. These variations are inherited and increase the chances of survival of an organism.

1. In sexual reproduction variations may occur due to errors in DNA copying.
2. There may be variations due to interchange of homologous chromosomes during crossing over of male and female.
3. In sexual reproduction, it is not predetermined that which gamete would fuse with another gamete. It depends only on chance. It is also a reason of variation.
   These variations enable the organisms to adapt themselves to the changing conditions and also help to give rise to new species.

જવાબ : Genetic material in most organisms is present in pairs of chromosomes. Gametes in the sexually reproducing organisms are formed by the process of meiosis during which half of the genetic material goes into each gamete. When the gametes from male and female parents fuse with each other during sexual reproduction, the normal complement is restored. Half of the genetic material comes from the female and half from the male.

જવાબ : Fossils play important role in providing evolutionary evidences because by knowing the age of fossils we can know about the evolution process of an organism.
For example, a fossil bird called archaeopteryx that looked like a bird had many other features of reptiles. It had feathered wings like those of birds, but teeth and tail like those of reptiles. Archaeopteryx is, therefore, a connecting link between the reptiles and birds, and hence suggests that the birds have evolved from the reptiles.

જવાબ : Classification of organisms is based on relative similarities and differences among organisms. Resemblances in organisms are because they have arisen from a common ancestor and differences in them are due to adaptations to different types of environment. Since the organisms can be graded in order of increasing complexity it indicates at the concept of evolution.

જવાબ : Bacteria are a primitive organism as they came into being very early in evolution. But these organisms are still surviving in the present conditions after millions of years. This is because they have adapted well to the changing environment over these years. Same is the case for all other organisms like spiders, fishes and chimpanzees which have adapted to their environment and have survived. Therefore, all the organisms which exist have a body design which is better as it is suited to their environment.

જવાબ : This is because although genetic makeup of humans may be slightly different in different races of people, there is no reproductive isolation. Reproductive isolation differentiates one species from the other. Human beings different in size, color and looks can marry among themselves and produce fertile offspring.

જવાબ : Fossils: Fossils are the remains or traces of a dead organism. These are formed through the formation of sedimentary rocks. They provide following information on the process of evolution.

1. They tell about the changes that occurred on the earth’s surface and the corresponding organisms.
2. They tell about the gradual development of complex structured organisms from simple structured organisms.
3. It is known through them that birds are evolved from reptiles.
4. They state that angiosperms are developed from pteriodophytes and gymnosperms.
5. They exhibit the process of human evolution.

જવાબ : The factors that would lead to the rise of a new species are the following:

1. Geographical isolation of a population caused by various types of barriers (such as mountain ranges, rivers and sea). The geographical isolation leads to reproductive isolation due to which there is no flow of genes between separated groups of population.
2. Genetic drift caused by drastic changes in the frequencies of particular genes by chance alone.
3. Variations caused in individuals due to a natural selection.

જવાબ : Mendel took pea plants with contrasting characteristics tall plant and dwarf (or short) plant. On cross pollination, he got all tall plants in first generation (F₁). But by the self-pollination of F₁ tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3: 1. On the basis of these experiments, the characteristics appeared in first generation were called dominant (i.e. tall plants) and the characteristics that did not appear were called recessive (dwarf i.e. plants).

જવાબ : The variations provide stability to the population of various species by preventing them from getting wiped out during adverse conditions.
The natural environment also changes, and variations in species which become suited to the environment help it to survive.

જવાબ : We agree with the statement that solely variations that confer a plus to a private organism can survive during a population. All the variations don’t have associate equal likelihood of extant within the setting within which they notice themselves. The possibilities of extant rely upon the character of variations. Totally different individuals would have different reasonably benefits. Bacterium which will face up to heat will survive higher during a wave. Choice of variants by environmental factors forms the idea for revolutionary method.

જવાબ : The inheritance of equal parent chromosomes ensures equal genetic contribution within the relative of male and female folk. There are 23 pairs of chromosomes. There is no pairing of all human chromosomes. The primary twenty-two trials are called autonomies out of those twenty-three pairs, and the remaining one pair is also thought to be sex chromosomes drawn as X and Y. Females have an ideal trial of 2 X sex chromosomes and males have an inappropriate trial of 1 X and 1 Y chromosome.

જવાબ : Sexual reproduction causes a lot of viable variations because of the subsequent reasons:

જવાબ : The evidence of the origin of the inanimate matter in life was provided by Stanley L. Miller and Harold C. Urey’s associate degree experiment conducted in 1953. They assembled an environment in experiment that contained molecules such as ammonia, alkanet series and element sulfide over water, but no chemical element. It was just like the atmosphere on earth that thought it would exist. This was kept at a temperature slightly below 100 ° C and the mixture of gasses to simulate lightning was felt by sparks. At the end of the week, fifteenth of the alkanet series carbon has been regenerated into easy carbon compounds as well as amino acids that form super molecule molecules and support basic life. It was inferred from this that life arose again on earth.

જવાબ : Fossil give evidence about

જવાબ : Dogs have a spread of genes that govern coat color. There are a minimum of eleven known sequence series (A, B, C, D, E, F, G, M, P, S, T) that influence coat change dog. A dog inherits one sequence from every of its oldsters. The factor gets expressed within the constitution. As an example, within the B series, a dog is genetically black or brown. Allow us to assume that one parent is homozygous black (BB), whereas the opposite parent is homozygous brown (bb).

જવાબ : Homologous organs are those organs that have the identical basic structural style and origin, however have completely different functions. For example: The forelimbs of humans and also the wings of birds look completely different outwardly however their complex body part is comparable.

જવાબ : Correct answer – (b)

જવાબ : Fossils are called the preserved remains of animals or plants or other organisms from the distant past. These fossils tell us about a lot of extinct animals and also give insights into how evolution might have occurred. Fossils can be used to build an organism’s evolutionary history. The pattern of fossil distribution gives us an idea of the time in history when various species were formed or become extinct. Fossil also helps trace some animal’s evolutionary history.

જવાબ : Let us take the instance of humans and apes. Each of them has similar body style. Hair and exocrine gland glands are gifting in each the animals. Hence, these 2 animals are closely connected in organic process term. Currently take some common characters between a fish and a person. Rachis, brain box and jaws are gift in each of them. However fish and man look entirely different from one another. Hence, they’re not closely connected in organic process term; rather are like distant relatives.

જવાબ : Factors that would cause the increase of a brand new species are as follows:

જવાબ : As the tiger population is decreasing sharply, the genetic pool of the tigers is additionally decreasing. This results in a limitation on the variations which will be introduced within the genetic makeup of the tigers. This might need serious implications. For example, if a un-wellness spreads within the tiger population, it would swipe the whole population while not going any survivors. This might even cause their extinction.

જવાબ : An individual attribute could increase in a population within the following 2 ways:-

જવાબ : Sex of child in humans is set by the sort of male haploid sex cell that fuses with the feminine egg. Throughout meiosis, all the gametes created by females contain solely the X chromosome (A + X), whereas males manufacture 2 varieties of gametes, 1/2 gametes with X- and 1/2 with Y-chromosome (A + X and A + Y). Fertilization of egg (A + X) with sperm cell carrying A+X chromosomes ends up in female descendant (AA + XX). Fertilization of egg (A+ X) with sperm cell carrying A+ Y chromosomes ends up in teenager (AA + XY).

જવાબ : Law of independent assortment tells regarding segregation and distribution of things governing 2 totally different traits. Consequently, genes for the 2 traits gift on separate chromosomes are inheritable severally of every alternative. Throughout hybridization by plant scientist, it had been determined that once 2 pairs of attributes were considered; every trait expressed freelance of the opposite. For example Cross between a plant manufacturing spherical and yellow seeds (RR and YY) crossing with a plant producing wrinkled inexperienced seeds (err and by).

જવાબ : According to law of dominance, an attribute is painted by 2 contrastive factors of a factor during a heterozygous individual; the allele/factor that may specific itself in heterozygous individual is named as dominant trait. The opposite issue, whose impact is cloaked by presence of dominant factor, is named recessive issue. Once Johann Mendel crossed one tall and one short leguminous plant, all the off springs (F1 generation) were tall. Once he self-crossed the F1 generation, among them 3/4th of the progenies were tall whereas 1/4th were short. So he ended that though the F1 relation had each tall and short traits, solely tall plants were discovered within the F1 generation, this implies that tallness may be a dominant attribute.

જવાબ : This information is not enough. This is because each individual is carrying two alleles. The recessive trait can occur only when who alleles are similar. It blood group A is dominant and O is recessive, then daughter can have blood group O only when both recessive alleles occur together in mother, and father has one allele of O and other of A.

જવાબ :

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

જવાબ :

જવાબ :

a. Acquired
b. Traits
c. DNA
d. Progeny

જવાબ :

a. Fossil
b. Species
c. Gene
d. Inherited
e. Reproduce
f. Gene