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: (c)
The two oviducts in the human female body unite to form an elastic bag-like structure, which is called the uterus. The uterus is a crucial part of the female reproductive system where the fertilised egg implants and the fetus grows during pregnancy.

Q2: Which of the following disease is transmitted sexually?
(a) Kala azar
(b) Jaundice
(c) Cholera
(d) Syphilis
Ans: (d)
Syphilis is a sexually transmitted disease. It is caused by the bacterium Treponema pallidum and can be spread through sexual contact including vaginal, anal, and oral sex. Other diseases like Kala azar, Jaundice and Cholera are not sexually transmitted.

Q3: Which of the following is a contraceptive?
(a) Copper
(b) Condom
(c) Diaphragm
(d) All of these
Ans: (d)
All the options given here, Copper (as in Copper T - an intrauterine device), Condoms and Diaphragm are different types of contraceptives. They are used to prevent pregnancy. These methods either prevent sperm from reaching the egg or stop the egg from implanting itself in the uterus wall.

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)
The process where an animal is cut into pieces and each piece grows into a complex organism is called Regeneration. Some organisms like starfish, hydras, and planarians use this form of asexual reproduction to create new organisms.

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)
In grafting, the portion which provides the roots is called the Stock. The stock is the existing plant onto which the scion (the part of the plant to be propagated) is grafted.

Q6: Where does fertilization occur in human females?
(a) Uterus
(b) Cervix
(c) Oviduct
(d) None of these
Ans: (c)
Fertilization in human females, the fusion of the sperm and the egg, occurs in the oviduct (or the fallopian tube). This is where the sperm meets the released ovum and fertilization takes place.

Q7: Growing fetus derive nutrition from mother’s blood through
(a) Uterus
(b) Fallopian tube
(c) placenta
(d) cervix
Ans: (c)
The growing fetus derives nutrition from the mother's blood through the placenta. The placenta is a specialised organ that develops during pregnancy. It facilitates the exchange of nutrients, oxygen, and wastes between the mother and the fetus.

Q8: What is the puberty age in human males?
(a) 8-10
(b) 10-12
(c) 12-14
(d) 14-16
Ans: (c)
The puberty age in human males is generally between 12-14 years. During this period, boys undergo several physical changes including deepening of voice, growth of facial and pubic hair, and development of sexual organs.

Q9: Fruits are formed from
(a) Stamen
(b) Stigma
(c) Ovary
(d) Ovule
Ans: (c)
Fruits are formed from the ovary of a flower. After fertilization, the ovary grows and develops into a fruit, while the fertilized ovules develop into seeds.

Q10: IUCD is for
(a) Vegetative propagation
(b) Contraception
(c) Increasing fertility
(d) Avoiding miscarriage
Ans: (b)
IUCD stands for Intra Uterine Contraceptive Device. It is a device placed inside the uterus as a method of birth control to prevent pregnancy, thus it is used for 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)
The assertion that spores are unicellular bodies is correct as spores are indeed single-celled bodies that can grow into new individuals. However, the reason given is incorrect. The parent body does not just break up into smaller pieces on maturation. Instead, spores are produced by the parent body and are released when they mature. Hence, the answer is (c) A is true but R is false.

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)
Asexual reproduction is indeed a primitive type of reproduction, as it is found in less complex organisms and does not involve the fusion of gametes. The reason that asexual reproduction involves only mitotic cell division is also true, but it is not the correct explanation for the assertion. Asexual reproduction is primitive not just because it involves mitosis, but because it results in offspring that are genetically identical to the parent. Therefore, the answer is (b) Both A and R are true but R is not the correct explanation of A.

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)
The offspring produced by sexual reproduction adjust better in environmental fluctuations because there is a mixing of genetic material during the fusion of gametes. This genetic variation allows the offspring to adapt better to changing environmental conditions. Therefore, the answer is (a) Both A and R are true and R is the correct explanation of A.

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: (c)
The assertion that testes lie in the penis outside the body is false. Testes are located in the scrotum, not the penis. However, the reason that sperms require a lower temperature than the body temperature for development is true. Therefore, the answer is (d) A is false but R is true.

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)
It is true that unisexual flowers have separate male and female flowers and that a typical monocot embryo comprises an embryonal axis with a single cotyledon. However, the reason given, namely that cucumber, pumpkin and watermelon are examples of unisexual flowers, does not explain the assertion. These examples just illustrate the concept of unisexual flowers but do not provide an explanation for the assertion. Therefore, the answer is (b) Both A and R are true but R is not the correct explanation of A.

Case Study Based Questions

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
The incidence indicates that Bryophyllum has a unique property to reproduce through leaves, a process known as vegetative propagation. This means that new plants can grow from the leaves of the plant when they fall on the ground. This is because the leaves of Bryophyllum have special buds that germinate to give rise to new plants. Both (a) and (b) are correct, as they explain the process of vegetative propagation in Bryophyllum, making option (d) the correct answer.

Q2: Which of the following plants can propagate vegetatively through leaves like Bryophyllum?
(a) Guava
(b) Begonia
(c) Ginger
(d) Mint
Ans: B
Among the options, Begonia is a plant that can also propagate vegetatively through its leaves like Bryophyllum (Option B). This means that leaves of Begonia, when detached from the plant and placed on the ground, can give rise to new plants.

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
Other than leaves, the stem of Bryophyllum can also help in propagation. This is because the stem of Bryophyllum, like its leaves, can give rise to new plants when cut and planted in the ground. This method of reproduction is also a part of vegetative propagation. Therefore, the correct answer is (b) Stems.

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
Among the given options, the Rose plant is artificially propagated vegetatively by stem cuttings in horticultural practices. This means that new rose plants are often grown from the cuttings of the stem of a mature rose plant. Potato, Snake plant, and Water hyacinth are not typically propagated this way. Therefore, the correct answer is (c) Rose.

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.
Q5: 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
Menstruation stops in a pregnant female because of all the reasons mentioned. The egg gets fertilised and does not need to be expelled (option a). Moreover, ovulation, which is the release of eggs, stops during pregnancy leading to the cessation of menstruation (option b). Lastly, the uterine lining becomes thick and is retained for the proper development of the embryo (option c). Hence, all of these reasons collectively contribute to the stopping of menstruation during pregnancy.

Q6: 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
The correct sequence that leads to pregnancy starts with ovulation, which is the release of an egg (B). This is followed by fertilization, where the egg is fertilised by a sperm (A). The fertilised egg, now called a zygote, begins to divide and grow (C), eventually getting implanted in the uterus' lining (D). Thus, the sequence is B→A→C→D.

Q7: 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
A zygote is different from an embryo in that a zygote is single-celled, formed from the fertilisation of the egg by a sperm (option c). On the other hand, an embryo is multicellular, developed from the zygote through repeated cell divisions. So, an embryo is a more advanced stage of development compared to a zygote.

Q8: 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
During pregnancy, the uterus undergoes significant changes. The uterine lining becomes thick and vascular to support the growing embryo (option a). Simultaneously, the placenta develops, which links the embryo to the mother through the umbilical cord (option b). This helps in the exchange of nutrients and wastes between the mother and the growing fetus. So, both options (a) and (b) are correct.

Very Short Answer Type Question

Q1: Define vegetative propagation.
Ans: Vegetative propagation is an asexual method of plant reproduction that occurs in its leaves,roots and stem.

Q2: What are the agents of pollination?
Ans: Pollinating agents can be animals such as insects, birds, and bats; water; wind; and even plants themselves,

Q3: Name the vegetative parts used in Bryophyllum and sugarcane for propagation.
Ans: Reproduction in Bryophyllum occurs asexually through vegetative propagation by leaves. The leaf of Bryophyllum is broad and has notches at its margins. ... Sugarcane has a thick, tillering stem which is clearly divided into nodes and internodes.

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

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

Short Answer Type Question

Q1: Define the terms unisexual and bisexual giving one example of each.
Ans:

• 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.

Q2: How does leishmania and Planaria reproduce differently ?
Ans: Leishmania reproduces by binary fission and Plasmodium reproduce by multiple fission.

• Binary fission: It occurs under favourable conditions and gives rise to two individuals .
• Multiple fission: It occurs under both favourable and unfavourable conditions and forms several individual.

Q3: How does bryophyllum produce new plants?
Ans: Bryophyllum can be reproduced by vegetative propagation by using either a piece of its stem or leaves. The leaves of a Bryophyllum plant have special buds in their margins which may get detached from the leaves, fall to the ground and then grow to produce a new plant.

Q4: How does rhizopus reproduce?
Ans: Fungi and some algae reproduce asexually through spores. Rhizopus is a fungus and is commonly called bread mould.
Rhizopus grows as fine thread-like projections known as hyphae. Present on the top of hyphae is a blob-like structure, called sporangia. Sporangia produce numerous reproductive bodies called spores. Spores germinate under moist conditions to grow into new Rhizopus species.

Q5: Exlain how human embryo get nourished in mother body?
Ans: The embryo gets nourishment inside the mother body through a special tissue called placenta. The embryo grows inside the mother's womb and gets nourishment from mother's blood through the tissue called placenta. The placenta is a temporary organ that develops in the uterus during pregnancy.

Q6: What changes occur in the flower after fertilisation?
Ans: After fertilisation the flower withers. The sepals and the petals dry up, the ovary converts into fruit, the ovule forms the seed and the zygote forms the embryo which is enclosed in the seed.

Q7: How do potato and Bryophyllum plants reproduce vegetatively?
Ans: Potato tuber has depressions called ‘‘eyes’’ on its surface. These eyes have vegetative buds in them which germinate to produce a new potato plant. Similarly the fleshy leaves of Bryophyllum bear vegetative buds in the notches along the leaf margin. These buds germinate to form small plantlets which form new plants on being detached.

Q8: What is the significance of sexual reproduction?
Ans:

• A sexual reproduction results in new combination of characters and increases genetic variations.
• It promotes diversity of characters in the offspring.
• It speeds up the process of making variations in the population.

Q9: What is regeneration? Name two organisms that can reproduce by regeneration.
Ans: Many fully differentiated organisms have the ability to give rise to new organisms from their body parts by being cut or broken into many pieces. This is known as regeneration. All organisms do not have the capacity to reproduce by regeneration.
Hydra and Planaria can reproduce by the process of regeneration.

Q10: State the changes that occur in human males and females at puberty.
Ans: The changes that take place in males during puberty are growth of hair on the body, appearance of beard and moustache and the voice becomes hoarse. Females show development of breasts, and beginning of menstruation.

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: Form the male gametes the sperms and secrete the male sex hormone testosterone
(b) Ovaries: Form the female gamete ovum or the egg cell and secrete the female sex hormones estrogen and progesterone.
(c) Vas deferens: Transport the sperms from the testis to the exterior.
(d) Stamen: Form the pollen grains in flowers. The pollen grains bear the male gametes.
(e) Pistil: The ovary forms the egg and the stigma helps in attracting the pollen grains for fertilisation.

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

• It helps in the easy propagation of non–flowering plants.
• It helps in producing hybrids of various plants, with improved qualities.
• It helps in the propagation of a large number of populations in a very short duration.
• It helps in the propagation of plants that do not produce seeds or produce them in very small quantities 

Q3: Explain various steps of budding in yeast.
Ans: Budding is a form of asexual reproduction usually observed in yeast.
During this process, a small protrusion appears on the upper portion of the body of the organism. This bulge is called a bud.

• The bud gradually grows in size and forms an individual cell.
• From this newly budded cell, another bud appears at the tip.
• This process continues and many chains of buds are formed

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

• It helps a species to survive
• It also helps organisms to adapt to their environment as well as to changes which do occur in the environment.
• It also helps a species to emerge strongly favoured by natural selection.
• Variation helps a species to be resistant to diseases.

Q5: Describe various methods of asexual reproduction in organisms with suitable examples?
Ans: Asexual reproduction:

• It is a form of reproduction in which a single parent produces a new offspring.
• The new individuals developed are exact copies of their parents.
• They are clones of their parents.

Various methods of asexual reproduction:

Vegetative propagation

• In vegetative propagation, new plants are produced from roots, stems, leaves, and buds.
• It is a form of asexual reproduction.
  • Examples: Tuber of potato, the rhizome of ginger

Budding

• Bud is a small outgrowth that grows and gets detached from the parent body.
• The new detached bud grows, matures, and produces more buds.
  • Examples: Hydra

Fragmentation

• In this mode of reproduction, the growth is done by rapidly breaking down into more fragments.
• When resources (water and nutrients) are available these fragments grow into new individuals.
  • Examples: Algae

Fission

• Unicellular organism splits into new organisms.
• There are two types of fission:
  • Binary fission (Amoeba, paramecium, etc.)
  • Multiple fission (Plasmodium)

Spore Formation

• Reproduction is done by spores.
• Under favorable conditions germinate and develop into a new individual.