Class 9 Science, Chapter 11 (NCERT). 8 questions by concept. Open “Show answer” for the answer and why.
How to teach this chapter · Common misconceptions & worked visual for this chapter
A new potato plant grows from an eye on a tuber. What process is this?
(b) Vegetative propagation
A potato tuber is an underground stem, and its eye is a bud. Growth of a new plant from this stem part is vegetative propagation. It involves neither seed germination nor fusion of gametes.
How does a Hydra bud's genetic material compare with its parent's?
(b) An almost identical copy of the parent's
A Hydra bud develops from one parent without gamete fusion. It inherits a copy of that parent's genetic material, so the two are almost identical.
What happens during pollination?
(a) Transfer of pollen from the anther to the stigma
Pollination is the transfer of pollen from the anther to the stigma. Fusion of the male gamete with the egg is fertilisation. Pollen grains are not seeds.
After fertilisation in a flower, which structure develops into the seed?
(b) The ovule
After fertilisation, the zygote develops into an embryo within the ovule. The ovule develops into the seed.
Where do fertilisation and implantation usually occur in humans?
(a) Fertilisation occurs in an oviduct; implantation occurs in the uterus.
The zygote forms in the oviduct and later attaches to the uterine lining.
Which contraceptive method helps reduce both pregnancy risk and the risk of many sexually transmitted infections?
(a) Condoms
Condoms form a physical barrier that limits sperm movement and the exchange of infectious body fluids. Oral pills and Copper-T help prevent pregnancy but do not protect against sexually transmitted infections.
A human body cell has 46 chromosomes. How many chromosomes are in each gamete formed by meiosis?
(b) 23
Meiosis halves the chromosome number: . Each human gamete therefore has 23 chromosomes. Fertilisation joins two gametes, restoring 46 chromosomes in the zygote.
What produces new combinations of genetic information during sexual reproduction?
(a) Mixing of genes during meiosis and fusion of gametes from two parents
Meiosis produces gametes with different combinations of genes. Fertilisation combines genetic information from two parents, contributing to variation among offspring. Meiosis halves the chromosome number; fertilisation restores it.
Wrong
Every living thing needs two parents to reproduce.
Why it feels right. Animal reproduction is the example I know best.
Right
Asexual reproduction can occur from one parent.
Worked example
