How Do Organisms Reproduce

Define variations in relation to a species. Why is variation beneficial to the species?

Why is DNA copying an essential part of the process of reproduction?

What is reproduction? Mention the importance of DNA copying in reproduction.

For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:

a. Both A and R are true, and R is correct explanation of the assertion.

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

c. A is true but R is false.

d. A is false but R is true.

Assertion: Seeds are matured ovules.

Reason: The part of seed which contains stored food for baby plant is called cotyledon.

For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:

1. Both A and R are true, and R is correct explanation of the assertion.
2. Both A and R are true, but R is not the correct explanation of the assertion.
3. A is true but R is false.
4. A is false but R is true.

Assertion: Internal fertilisation occurs in mammals and birds.

Reason: External fertilisation occurs in reptiles, amphibians, and fishes.

Mention the common mode of reproduction found in

• Amoeba
• Planaria.

Name one sexually transmitted disease each caused by a bacterial infection and viral infection. How can they be prevented?

What is reproduction? What are the two types? Which one of the two confers new characteristics on the offspring and how?

(a) In human body what is the role of

• seminal vesicles and
• prostate gland.

(b) List two functions performed by testes in human beings.

Mention the information source of making proteins in the cell. What is the basic event in reproduction?

List any two differences between pollination and fertilization.

What is vegetative propagation?

Read the following and answer any four questions from (i) to (v).

A married woman used a device X made of common metal for preventing pregnancy. This device was put into her uterus by some trained medical professional. Unfortunately, she got pregnant after two months of insertion of device. She was in shock to learn that her birth control device has failed.

(i). What is the name of birth control device used by the woman?

1. Foam tablets.
2. Copper T.
3. Diaphragm.
4. Both (a) and (b).

(ii). Which metal is commonly used for making device X?

1. Iron.
2. Copper.
3. Silver.
4. Gold.

(iii). How does device X prevent pregnancy?

1. It prevents ovulation.
2. It prevents copulation.
3. It suppresses fertilising capacity of sperm.
4. None of these.

(iv). Why do you think the woman got pregnant even after using device X?

1. Device X might have got expelled without the knowledge of woman.
2. Device X might be defective and was not working from the beginning.
3. Device X could have been destroyed by the uterine fluid.
4. None of these.

(v). Select the correct statement regarding device X.

1. Device X is very effective in preventing sexually transmitted diseases.
2. Device X can be inserted in uterus by woman herself.
3. Device X prevents menstrual cycle in women.
4. Device X can cause heavy painful and longer duration periods or menstruation.

Name the male and female gametes in animals. What is fertilization and where does it take place in human females?