📝 Page 128

Q1: What is the importance of DNA copying in reproduction?

Ans: DNA copying is important in reproduction because it ensures that the genetic information is passed from parents to offspring. This allows the organism to maintain its identity and characteristics. Minor variations due to inaccuracies in DNA copying can lead to evolution over generations.

Q2: Why is variation beneficial to the species but not necessarily for the individual?

Ans: Variation helps a species survive in changing environments. If all individuals were identical, a single change could wipe out the whole population. However, variation is not always beneficial to an individual because it may result in disadvantageous traits.

📝 Page 133

Q1: How does binary fission differ from multiple fission?

Ans: In binary fission, a single organism splits into two daughter cells (e.g., Amoeba). In multiple fission, the organism divides into many daughter cells simultaneously (e.g., Plasmodium).

Q2: How will an organism be benefited if it reproduces through spores?

Ans: Reproduction through spores helps organisms survive in unfavorable conditions. Spores are lightweight, can be dispersed easily, and can remain dormant for long periods until conditions become favorable.

Q3: Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

Ans: In complex organisms, cells are specialized and organized into tissues and organs. Regeneration of the whole organism is not possible because simple cell division cannot recreate the complete body structure and functions.

Q4: Why is vegetative propagation practiced for growing some types of plants?

Ans: Vegetative propagation is practiced because:

• It is faster.

• It produces genetically identical plants.

• It helps preserve desirable traits.

• It enables propagation of plants that do not produce viable seeds.

Q5: Why is DNA copying an essential part of the process of reproduction?

Ans: DNA copying is essential because it passes genetic information to the next generation, enabling the continuity of life and maintaining the organism’s characteristics.

📝 Page 140

Q1: How is the process of pollination different from fertilization?

Ans:

• Pollination is the transfer of pollen from the anther to the stigma.

• Fertilization is the fusion of male and female gametes to form a zygote.

Q2: What is the role of the seminal vesicles and the prostate gland?

Ans: The seminal vesicles and prostate gland secrete fluids that nourish the sperm and make their transport easier by forming semen.

Q3: What are the changes seen in girls at the time of puberty?

Ans:

1. Hair grow under armpits and pubic region.
2. Mammary glands (or breasts) develop and enlarge.
3. The hips broaden.
4. Ovaries start to release eggs.
5. Menstruation (monthly periods) starts.

Q4: How does the embryo get nourishment inside the mother’s body?

Ans: The embryo receives nourishment through the placenta, a special tissue that connects it to the mother’s uterus. The placenta supplies oxygen and nutrients and removes waste.

Q5: If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?

Ans: No. A copper-T prevents pregnancy but not sexually transmitted diseases (STDs). Only barrier methods like condoms can prevent STDs.