1. Why is DNA copying essential? DNA carries genetic
information. Copying ensures traits pass to offspring. Slight variations during copying create genetic
diversity for evolution.
2. Why can't regeneration be called reproduction?
Regeneration is regrowth of lost parts (repair). Reproduction creates entirely new organisms. Cutting a
lizard's tail doesn't create a new lizard.
3. Why do organisms reproduce even though it's not essential for
survival? Reproduction ensures continuation of the species. Without it, the species would
become extinct when existing members die. It's essential for species survival, not individual survival.
4. How does the embryo get nutrition? Initially from the
mother's blood via Placenta. The placenta has villi that exchange gases, nutrients, and waste between mother
and foetus through the umbilical cord.
5. Why is awareness about contraception important? Controls
population growth, prevents unwanted pregnancies, helps in family planning, reduces maternal and infant
mortality.
6. Types of Contraceptive Methods:
Barrier: Condoms, diaphragm (block sperm).
Hormonal: Pills (prevent ovulation).
Intrauterine: Copper-T (prevents implantation).
Surgical: Vasectomy (male), Tubectomy (female).
7. Why are surgical methods considered permanent? Vasectomy
cuts vas deferens, tubectomy cuts/blocks fallopian tubes. These procedures are difficult (sometimes
impossible) to reverse.
8. Advantages of Vegetative Propagation: (a) Faster than
seed germination. (b) Produces genetically identical offspring (clones) with desired traits. (c) Plants that
don't produce seeds can reproduce.
9. Disadvantages: (a) No genetic variation (vulnerable to
diseases). (b) Only possible in certain plants. (c) Cannot survive extreme conditions like seeds.
10. Tissue Culture: Growing plants from small tissue pieces
in artificial medium. Used for mass production of disease-free plants (orchids, bananas).
11. Assertion: Flowers are called reproductive organs of
plants.
Reason: Flowers contain both male (stamen) and/or female (pistil) reproductive parts.
Pollination, fertilization, seed and fruit formation all occur in/around the flower.
Both A and R are True, R is correct explanation of A.
12. What happens if both ovaries are removed? No egg
production (ovulation stops), menstrual cycle stops immediately (surgical menopause), pregnancy becomes
impossible, hormone levels drop significantly.
