Assertion Reason Science CBSE 10th Chapter 8: How Do Organisms Reproduce?

Assertion Reason Science CBSE Class 10 Chapter 8 How Do Organisms Reproduce, To solve assertion reason type questions of science, deeper understanding of concept about our reproduction is required. In order to help the student in solving Assertion Reason type of questions, detailed process is explained.

How to solve Assertion Reason Type Questions ?
In Assertion-Reason type of question, two statements are given, first is Assertion and second is called Reason. Student must have to think critically about both the statements in Assertion Reason Questions, since it combines multiple choice questions and true/false type of questions which requires a higher level of understanding.

In assertion reason type of questions, all 5 options are same for each question, which are as:

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(e) Both Assertion and Reason are false.

Then a question haunts in every student’s mind, which option is correct and when?
This can be understood clearly with the following table:

Assertion (A)Reason (R)MCQ Options (Fixed for all questions)
If TrueTrue(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
If TrueTrue(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
If TrueFalse(c) Assertion (A) is true but reason (R) is false.
If FalseTrue(d) Assertion (A) is false but reason (R) is true.
If FalseFalse(e) Both Assertion and Reason are false.

Now, lets practice some Assertion Reason Questions of Science Chapter 8 How Do Organisms Reproduce.

Directions: Mark the option which is most suitable :
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.

Question.1.
Assertion : Amoeba shows multiple fission during unfavorable conditions.
Reason : Chances of survival are less during unfavourable conditions.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question.2.
Assertion : Plasmodium reproduces by multiple fission.
Reason : Multiple fission is a type of asexual reproduction.

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

Explanation: Plasmodium prproduces asexually by multiple fission.

Question.3.
Assertion : In human male, testes are extra-abdominai which are present inside scrotum.
Reason : Scrotum has a relatively lower temperature needed for the production and storage of sperms.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Formation of sperms needs lower temperature than the normal body temperature. Hence, testes lie outside the body cavity in the scrotum.

Question.4.
Assertion : At puberty, in boys, voice begins to crack and thick hair grows on face.
Reason : At puberty, there is decreased secretion of testosterone in boys.

(c) Assertion (A) is true but reason (R) is false.

Explanation: Puberty in boys is regulated by male sex hormone called testosterone, which are secreted by testes. In puberty, secondary sexual characters like growth of hair on face, chest, broadening of shoulders and deepening of voice occurs.

Question.5.
Assertion : Spores are unicellular bodies.
Reason : The parent body simply breaks up into smaller pieces on maturation.

(c) Assertion (A) is true but reason (R) is false.

Question.6.
Assertion : Surgical methods are most effective methods of contraception.
Reason : Surgical method blocks gametes transport and hence prevent fertilisation.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Surgical method like vasectomy in male and tubectomy in female prevent pregnancy. These methods block gamete transport and hence prevent fertilisation. They are very effective but reversibility is very poor.

Question.7.
Assertion : Asexual reproduction is a primitive type of reproduction.
Reason : Asexual reproduction involves only mitotic cell division.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question.8.
Assertion : Clones are offspring of an organism formed by asexual reproduction.
Reason : Clones have exact copies of DNA as their parent.

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

Question.9.
Assertion : Colonies of yeast multiply in sugar solution.
Reason : Sugar is made of sucrose which provides energy for sustaining all life activities.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question.10.
Assertion : DNA copying is necessary during reproduction.
Reason : DNA copying leads to the transmission of characters from parents to offspring.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: DNA copying is necessary during reproduction because it leads to the transmission of characters from parents to offsprings and brings about variation.

Question.11.
Assertion : Holoblastic cleavage with almost equal sized blastomeres is a characteristic of placental animals.
Reason : Eggs of most mammals, including humans, are of centrolecithal type.

(c) Assertion (A) is true but reason (R) is false.

Question.12.
Assertion : Sexual reproduction increases genetic diversities and plays a role in origin of new species.
Reason : Sexual reproduction involves formation of gametes and fusion of gametes.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Sexual reproduction involves two parents that results in the off springs that are not identical to the parents. If causes variations; which are essential for evolution as well as survival of species under unfavourable conditions.

Question.13.
Assertion : An embryo is formed from fertilized egg.
Reason : A monocot embryo comprises embryonal axis with two cotyledons.

(c) Assertion (A) is true but reason (R) is false.

Explanation: Zygote, a fertilized egg give rise to an embryo, which has the ability to develop into a complete plant. A typical dicot embryo comprises an embryonal axis with two cotyledons.

Question.14.
Assertion : Scrotum is present outside the abdominal cavity.
Reason : It stores sperms which require a lower temperature than the normal body temperature.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Scrotum, a pouch containing testis is present outside the abdominal cavity because sperms require a lower temperature than the normal body temperature.

Question.15.
Assertion : Vagina is also called as birth canal.
Reason : During birth, the baby passes through the vagina.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Vagina is called as birth canal, because the baby passes through the vagina during birth.

Question.16.
Assertion : Individuals produced by asexual reproduction are known as clones.
Reason : They are known as clones because they are genetically identical.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: The new individuals produced after cell divisions in asexual reproduction are always genetically identical or clone to each other and their parents.

Question.17.
Assertion : Vasectomy is a surgical method or birth control.
Reason : In vasectomy, small portion of oviduct is cut or tied properly.

(c) Assertion (A) is true but reason (R) is false.

Explanation: Vasectomy is a surgical method for birth control in which small portion of the sperm duct is cut or tied properly.

Question.18.
Assertion : HIV-AIDS is a bacterial disease.
Reason : It spreads through sharing of food and water.

(e) Both Assertion and Reason are false.

Explanation: HIV-AIDS is viral disease that is transmitted sexually. It is one of the STDs.

Question.19.
Assertion : In human male, there are perianal glands near the anus.
Reason : Perianal glands secrete sex-attractant pheromone which initiates sexual desire in human female.

(d) Assertion (A) is false but reason (R) is true.

Question.20.
Assertion : Amoeba reproduces by Binary fission.
Reason : All unicellular organisms reproduce asexually.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Amoeba is a unicellular organism. It reproduces asexually through binary fission. It is the division of one cell into two similar or identical cells.

Question.21.
Assertion : In morula stage, cells divide without increases in size.
Reason : Zona pellucida remain undivided till cleavage is complete.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question.22.
Assertion : Double fertilisation is unique to angiosperms.
Reason : Triple fusion occurs in both fertilization.

(c) Assertion (A) is true but reason (R) is false.

Explanation: Double fertilization is a characteristic feature of flowering plants. In this process, out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the secondary nucleus to form an endosperm (process is called triple fusion). Because two kinds of fusion-syngamy and triple fusion-take place, the process is known as double fertilisation.

Question.23.
Assertion : Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon.
Reason : Cucumber, pumpkin and water melon are example of unisexual flowers.

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

Explanation: Unisexual flowers have separate male and female flowers. The example includes cucumber, pumpkin and watermelon.

Question.24.
Assertion : Plants are vegetatively propagated even though they bear seeds.
Reason : Potatoes reproduces through tubers, apples by cutting etc.

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

Explanation: Vegetative reproduction happens through the use of vegetative parts of the plants, such as leaves, stems, and roots to produce new plants or through gowth from specialized vegetative plant parts.

Question.25.
Assertion : Pollen grains from the carpel stick to the stigma of stamen.
Reason : The fertilised egg cells grow inside the ovules and become seeds.

(d) Assertion (A) is false but reason (R) is true.

Question.26.
Assertion : Characteristics of parental plants can be preserved through asexual reproduction.
Reason : Vegetative reproduction involves only mitosis.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Explanation: Asexual reproduction involves a single individual, which give rise to new individual that are genetically identical to parents. It is because, when organisms reproduce asexually, only mitotic divisions are involved and the chromosome number remains the same.

Question.27.
Assertion : Urethra in human male acts as urinogenital canal.
Reason : Urethra carries only urine while sperms are carried by vasa deferentia only.

(c) Assertion (A) is true but reason (R) is false. 

Question.28.
Assertion : During fertilization only head of spermatozoa enters egg.
Reason : If several spermatozoa hit the egg at same time, all can enter the egg.

(c) Assertion (A) is true but reason (R) is false.

Question.29.
Assertion : Asexual reproduction is also called blastogenesis.
Reason : In asexual reproduction, their is no formation and fusion of gametes.

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

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