How do Organisms Reproduce? Class 10 Worksheet Science

Multiple Choice Questions

Q1: The two oviducts in a human female unite into an elastic bag like is known as
(a) Vagina
(b) Uterus
(c) Fallopian tube
(d) Cervix
Ans: (b)
Explanation: The two oviducts (fallopian tubes) open into the single, muscular, elastic bag-like organ called the uterus. The uterus receives the fertilised egg, provides a protective environment and supports the developing embryo and fetus during pregnancy.

Q2: Which of the following disease is transmitted sexually?
(a) Kala azar
(b) Jaundice
(c) Cholera
(d) Syphilis
Ans: (d)
Explanation: Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum. It spreads mainly through sexual contact. The other listed diseases are not typically transmitted by sexual contact.

Q3: Which of the following is a contraceptive?
(a) Copper
(b) Condom
(c) Diaphragm
(d) All of these
Ans: (d)
Explanation: All three listed items are methods of contraception: copper refers to the Copper T (an intrauterine device), a condom is a barrier method and a diaphragm is a barrier device placed over the cervix. Each prevents pregnancy by stopping sperm from fertilising the egg or by preventing implantation.

Q4: When a animal is cut into pieces and each piece grows into a complex organism. What is the process?
(a) Budding
(b) Fragmentation
(c) Spore formation
(d) Regeneration
Ans: (d)
Explanation: Regeneration is the process in which an organism regrows lost or damaged parts; in some animals, such as starfish and planaria, each piece can grow into a complete individual. Fragmentation is related but generally refers to body breaking into fragments that then develop; the best term for whole organisms forming from cut pieces is regeneration.

Q5: Which is the portion on which grafting is done it provides the roots?
(a) Stock
(b) Scion
(c) Both a and b
(d) None of these
Ans: (a)
Explanation: In grafting, the stock is the plant that provides the roots and root system. The scion is the part grafted on to the stock and provides the desired shoot characteristics. Therefore the stock is the root-providing portion.

Q6: Where does fertilization occur in human females?
(a) Uterus
(b) Cervix
(c) Oviduct
(d) None of these
Ans: (c)
Explanation: Fertilisation of the egg by the sperm typically occurs in the oviduct (fallopian tube). The fertilised egg (zygote) then moves to the uterus for implantation.

Q7: Growing fetus derive nutrition from mother's blood through
(a) Uterus
(b) Fallopian tube
(c) placenta
(d) cervix
Ans: (c)
Explanation: The placenta is a specialised organ that connects the developing fetus to the mother's blood supply via the umbilical cord. It allows transfer of oxygen and nutrients to the fetus and removal of waste products.

Q8: What is the puberty age in human males?
(a) 8-10
(b) 10-12
(c) 12-14
(d) 14-16
Ans: (c)
Explanation: Puberty in human males commonly begins between 12 and 14 years of age. During this period secondary sexual characteristics develop, such as growth of facial and pubic hair, voice deepening and enlargement of reproductive organs.

Q9: Fruits are formed from
(a) Stamen
(b) Stigma
(c) Ovary
(d) Ovule
Ans: (c)
Explanation: After fertilisation the ovary of the flower develops into the fruit. The ovules inside the ovary become the seeds.

Q10: IUCD is for
(a) Vegetative propagation
(b) Contraception
(c) Increasing fertility
(d) Avoiding miscarriage
Ans: (b)
Explanation: IUCD stands for Intra Uterine Contraceptive Device. It is inserted into the uterus to prevent pregnancy and is thus a method of contraception.

Assertion & Reason Type Questions

Q1: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
Assertion (A): Spores are unicellular bodies.
Reason(R) : The parent body simply breaks up into smaller pieces on maturation.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (c)
Explanation:
(i) Assertion: Spores are unicellular bodies - this is true, spores are single-celled reproductive units produced by some fungi, algae and lower plants.
(ii) Reason: The parent body simply breaks up into smaller pieces on maturation - this is false; that description applies to fragmentation, not to spore formation. Spores are produced within specialised structures and then released.
(iii) Justification: Since the assertion is correct and the reason is incorrect, option (c) is appropriate.

Q2: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
Assertion(A) : Asexual reproduction is a primitive type of reproduction.
Reason (R) : Asexual reproduction involves only mitotic cell division.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (b)
Explanation:
(i) Assertion: Asexual reproduction is considered primitive - this is true because it is common in simpler organisms and does not involve fusion of gametes.
(ii) Reason: Asexual reproduction involves only mitotic cell division - this is also true in many cases, since offspring arise from mitotic divisions of the parent cell.
(iii) Justification: Although both statements are true, the reason (involving mitosis) does not fully explain why asexual reproduction is termed primitive; the term refers more to the absence of genetic recombination and the simpler organisation of organisms that use it. Hence option (b) is correct.

Q3: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
Assertion(A) : The offspring produced by sexual reproduction is likely to adjust better in environmental fluctuation.
Reason (R) : During the fusion of gametes there is mixing of genetic material from Two parents.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (a)
Explanation:
(i) Assertion: Offspring from sexual reproduction can adjust better to environmental fluctuations - true, because genetic variation increases the chance that some individuals will survive changes.
(ii) Reason: Fusion of gametes mixes genetic material from two parents - true; this produces variation in offspring.
(iii) Justification: The reason correctly explains the assertion, so option (a) is correct.

Q4: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
Assertion (A): Testes lie in penis outside the body.
Reason (R): Sperms require temperature lower than the body temperature for development
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (d)
Explanation:
(i) Assertion: Testes lie in penis outside the body - this is false; testes are located in the scrotum outside the body, not in the penis.
(ii) Reason: Sperms require a temperature slightly lower than core body temperature for proper development - this is true; that is why testes are in the scrotum outside the abdominal cavity.
(iii) Justification: Since A is false and R is true, option (d) is correct.

Q5: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
Assertion (A): Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon.
Reason (R): Cucumber, pumpkin and water melon are example of unisexual flowers.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (b)
Explanation:
(i) Assertion: The definition is correct - unisexual flowers have either stamens or carpels, and monocot embryos usually have a single cotyledon - both parts of the assertion are true.
(ii) Reason: Cucumber, pumpkin and watermelon are examples of plants with unisexual flowers - this is true; they show separate male and female flowers.
(iii) Justification: The reason provides examples but does not explain why the assertion is true. Therefore option (b) is correct.

Case Study Based Questions

1. Read the following and answer the questions
Preeti is very fond of gardening. She has different flowering plants in her garden. One Day few naughty children entered her garden and plucked many leaves of Bryophyllum plant And threw them here and there in the garden. After few days, Preeti observed that new Bryophyllum plants were coming out from the leaves which fell on the ground.

Q1: What does the incidence sited in the paragraph indicate?
(a) Bryophyllum leaves have special buds that germinate to give rise to new plant.
(b) Bryophyllum can propagate vegetatively through leaves.
(c) Bryophyllum is a flowering plant that reproduces only asexually
(d) Both (a) and (b).
Ans: (d)
Explanation: Bryophyllum produces plantlets from special buds present along the margins of its leaves. When leaf pieces fall to the ground, these buds can grow into new plants. Both statements (a) and (b) correctly describe vegetative propagation by leaves.

Q2: Which of the following plants can propagate vegetatively through leaves like Bryophyllum?
(a) Guava
(b) Begonia
(c) Ginger
(d) Mint
Ans: (b)
Explanation: Begonia species can produce new plants from leaf cuttings in a manner similar to Bryophyllum. The other listed plants use different vegetative parts for propagation (for example, ginger from rhizomes).

Q3: Do you think any other vegetative part of Bryophyllum can help in propagation? If yes, then which part?
(a) Roots
(b) Stems
(c) Flowers
(d) Fruits
Ans: (b)
Explanation: Bryophyllum can also be propagated from stem cuttings. Stem pieces that have nodes and buds can develop into new plants when planted.

Q4: Which of the following plant is artificially propagated (vegetatively) by stem cuttings in horticultural practices?
(a) Potato
(b) Snake plant
(c) Rose
(d) Water hyacinth
Ans: (c)
Explanation: Roses are commonly propagated by stem cuttings in horticulture. Potato is typically propagated by tubers, snake plant by leaf or division, and water hyacinth spreads vegetatively but is not usually propagated by stem cuttings in horticulture.

2. Read the following and answer the questions
Menstrual cycle is the cycle of events taking place in female reproductive organs, under the control of sex hormones, in every 28 days. At an interval of 28 days, a single egg is released from either of two ovaries. Regular Menstrual cycle stopped abruptly in a married women. She got herself tested and was happy to discover that she is pregnant with her first baby.

Q1: Why menstruation stops in a pregnant female?
(a) The egg gets fertilised so need not to be expelled out of body
(b) Ovulation stops during pregnancy and so do menstruation
(c) Thick uterine lining is needed for proper development of embryo, so that it is retained
(d) All of these
Ans: (d)
Explanation: During pregnancy the released egg has been fertilised and retained, ovulation ceases and the thickened, vascular uterine lining is maintained to support embryo development. All three reasons together explain why menstruation stops.

Q2: Select the correct sequence of acts that leads to pregnancy in a female.
A. Fertilisation of egg
B. Ovulation
C. Formation of zygote
D. Implantation
(a) D ⇒⇒C ⇒⇒B ⇒⇒A
(b) B⇒⇒ A⇒⇒C⇒⇒D
(c) A ⇒⇒ B⇒⇒ C⇒⇒ D
(d) D⇒⇒ C⇒⇒ A ⇒⇒B
Ans: (b)
Explanation: The correct sequence is: first ovulation (B), then fertilisation of the egg by sperm (A), forming the zygote (C), followed by implantation of the developing embryo in the uterine wall (D). Thus B → A → C → D.

Q3: How is a zygote different from embryo?
(a) Zygote is formed by repeated division of embryo
(b) Zygote is formed by fusion of sperm and egg whereas embryo is formed by fusion of zygote with other zygote
(c) Zygote is single celled but embryo is multicellular
(d) Zygote is formed by fertilisation but embryo is formed without fertilization
Ans: (c)
Explanation: A zygote is the single cell formed immediately after fertilisation of an egg by a sperm. Through repeated cell divisions the zygote develops into a multicellular embryo. Therefore (c) correctly distinguishes the zygote from the embryo.

Q4: What change takes place in the uterus of a pregnant female?
(a) Uterine lining becomes thick and vascular
(b) Placenta develops which links the embryo to mother through umbilical cord
(c) Uterus lining containing lots of blood capillaries breaks down
(d) Both (a) and (b)
Ans: (d)
Explanation: During pregnancy the uterine lining becomes thick and richly supplied with blood vessels to nourish the embryo (a). The placenta also develops to connect the embryo to the mother's blood supply via the umbilical cord (b). Option (c) describes menstruation, not pregnancy.

Very Short Answer Type Question

Q1: Define vegetative propagation.
Ans: Vegetative propagation is an asexual method of plant reproduction in which new plants are produced from vegetative parts such as leaves, stems and roots without the formation of seeds.

Q2: What are the agents of pollination?
Ans: Pollinating agents include animals (insects, birds, bats), wind and water; some plants also use mechanisms like self-pollination.

Q3: Name the vegetative parts used in Bryophyllum and sugarcane for propagation.
Ans: Bryophyllum propagates by leaves (leaf-borne plantlets). Sugarcane propagates vegetatively by its stem (setts or stem cuttings with nodes).

Q4: Name any two organisms that reproduce by spores.
Ans: Rhizopus and mushroom reproduce by spore formation.

Q5: Name two sex hormones.
Ans: The two main sex hormones are estrogen and testosterone.

Short Answer Type Question

Q1: Define the terms unisexual and bisexual giving one example of each.
Ans: The terms unisexual and bisexual can be defined as follows:

• Unisexual: A flower is unisexual if it contains either stamens (male) or carpels (female), but not both. Example: Papaya, watermelon.
• Bisexual: A flower is bisexual if it contains both stamens and carpels in the same flower. Example: Hibiscus, mustard.

Q2: How does leishmania and Planaria reproduce differently ?
Ans: Leishmania reproduces by binary fission (a single cell divides into two). Planaria reproduce mainly by regeneration/fragmentation - when the body is cut into parts, each part can regenerate into a complete individual.

Q3: How does bryophyllum produce new plants?
Ans: Bryophyllum produces new plants vegetatively from special buds present along the margins of its leaves. When leaves with these buds fall onto the soil, the buds grow into new plantlets. Stem cuttings can also give rise to new plants.

Q4: How does rhizopus reproduce?
Ans: Rhizopus, a bread mould, reproduces asexually by forming sporangia on hyphae. Each sporangium contains many spores. When conditions are favourable, these spores are released and germinate to form new Rhizopus individuals.

Q5: Exlain how human embryo get nourished in mother body?
Ans: The embryo is nourished via the placenta, a temporary organ that develops in the uterus. The placenta allows transfer of nutrients and oxygen from the mother's blood to the embryo and removes waste products. The exchange is carried by the umbilical cord.

Q6: What changes occur in the flower after fertilisation?
Ans: After fertilisation the flower parts (petals and sepals) typically wither and fall, the ovary develops into a fruit and the fertilised ovules develop into seeds; the zygote inside the ovule develops into the embryo.

Q7: How do potato and Bryophyllum plants reproduce vegetatively?
Ans: Potato reproduces by tubers: eyes on the potato tuber are buds that sprout into new plants. Bryophyllum reproduces by plantlets formed on leaf margins, these plantlets grow into new plants when detached.

Q8: What is the significance of sexual reproduction?
Ans: The significance of sexual reproduction are as follow:

• Sexual reproduction introduces new combinations of characters and increases genetic variation.
• This variation helps species adapt to changing environments.
• It contributes to the process of natural selection and can increase resistance to diseases in a population.

Q9: What is regeneration? Name two organisms that can reproduce by regeneration.
Ans: Regeneration is the process by which some organisms regrow lost or damaged parts, and in some cases, each part can form a new individual. Examples include hydra and planaria.

Q10: State the changes that occur in human males and females at puberty.
Ans: At puberty males show growth of body and facial hair, voice deepening and development of reproductive organs. Females develop breasts and begin menstruation. Both sexes show overall growth and development of secondary sexual characteristics.

Long Answer Type Questions

Q1: State the functions of the following:
(a) testis
(b) ovaries
(c) vas deferens
(d) stamen
(e) pistil
Ans:
(a) Testis: Produce male gametes (sperms) and secrete the male sex hormone testosterone.
(b) Ovaries: Produce female gametes (ova) and secrete female sex hormones (estrogen and progesterone).
(c) Vas deferens: Transport sperms from the testis toward the urethra for release.
(d) Stamen: The male reproductive part of a flower that produces pollen grains containing male gametes.
(e) Pistil: The female reproductive part of a flower; the ovary within the pistil produces ova (eggs) and the stigma receives pollen for fertilisation.

Q2: List the advantages of vegetative propagation
Ans: The advantages of vegetative propagation are as follows:

• It allows rapid multiplication of plants and fast establishment of crops.
• It helps produce plants identical to the parent, preserving desirable traits and hybrids.
• It is useful for plants that do not produce viable seeds or produce seeds rarely.
• It aids propagation of non-flowering or difficult-to-seed plants.

Q3: Explain various steps of budding in yeast.
Ans: Budding is a form of asexual reproduction usually observed in yeast. During the process following steps are observed:

• A small outgrowth (bud) appears on the parent cell.
• The bud enlarges as the nucleus divides and one nucleus moves into the bud.
• The bud eventually detaches to form a new individual; repeated budding can form chains of cells.

Q4: What is the importance of variation in the survival of individuals?
Ans: Variations help in survival of the organism by many different ways:

• Variation increases the likelihood that some individuals in a population will survive environmental changes.
• It enables adaptation to new conditions and can lead to evolution by natural selection.
• It may provide resistance to diseases and help the species survive challenges.

Q5: Describe various methods of asexual reproduction in organisms with suitable examples?
Ans:  In asexual reproduction a single parent produces offspring that are genetically similar to the parent. These offspring are often called clones.

Various methods of asexual reproduction:

Vegetative propagation

• New plants arise from roots, stems or leaves without formation of seeds. Examples: Potato (tuber), ginger (rhizome).

Budding

• A small outgrowth or bud forms on the parent, grows and detaches to become a new individual. Example: Hydra.

Fragmentation

• The parent body breaks into fragments and each fragment grows into a new individual. Example: Some algae and starfish (in animals this is often called regeneration).

Fission

• A unicellular organism divides into two (binary fission) or many (multiple fission) new individuals. Examples: Amoeba (binary fission), Plasmodium (multiple fission).

Spore Formation

• Organisms produce spores which, under favourable conditions, germinate to form new individuals. Examples: Rhizopus, many fungi and some algae.