Railway Science (Biology-Reproduction in Animals) (Part-II)

Total Questions: 50

41. Which type of reproduction can bring greater diversity? [RRB Group D 25/09/2018 (Morning)]

Correct Answer: (a) Sexual
Solution:

Sexual reproduction involves the fusion of gametes from two different parents, resulting in offspring that inherit a unique combination of genetic material from each parent.
This process introduces genetic variation and diversity among the offspring. Asexual reproduction involves the production of offspring from a single parent, without the involvement of gametes or the fusion of genetic material.

42. Which one of these is found in human males only ? [RRB Group D 26/09/2018 (Morning)]

Correct Answer: (c) Y - chromosome
Solution:

Sex chromosomes: Humans have 23 pairs of chromosomes, of which one pair determines sex. Females: They typically have two X chromosomes (XX). Males: They typically have one X chromosome and one Y chromosome (XY).

43. In sexual reproduction, the parents contributes: [RRB Group D 26/09/2018 (Morning)]

Correct Answer: (b) Half of its genes
Solution:

Each parent has a diploid set of chromosomes (2n) with homologous pairs. Meiosis halves this to haploid (n) for gamete formation. Gametes carry one set of chromosomes randomly selected from each pair.
Fertilization restores diploid chromosome number in zygote. Zygote inherits genes equally from both parents through gametes.

44. Asexual reproduction takes place in : [RRB Group D 27/09/2018 (Morning)]

Correct Answer: (d) Lower animals and plants
Solution:

Asexual reproduction: A type of reproduction in which offspring are produced from a single parent cell and have the same genetic code as the parent. Examples - Plants, Protozoans, Sponges, Planaria etc. Somatic cells - cells in the body other than sperm and egg cells (which are called germ cells). These cells are diploid in nature.

45. Labour pain is caused by contractions in the walls of the______. [RRB Group D 27/09/2018 (Evening)]

Correct Answer: (d) uterus
Solution:

Labour pain (Labor contractions) - Periodic tightening and relaxing of the uterine muscle (Largest smooth muscle, present in the uterus). Lower abdomen - Two main organs including the uterus (womb) and part of the bowel in women. Ovary - Small, oval-shaped glands located on either side of the uterus. Gene - Physical and functional unit of heredity, made up of DNA.

46. If the chromosome number is 46 in a human being, how many chromosomes are present in somatic cells of the human being? [RRB Group D 28/09/2018 (Morning)]

Correct Answer: (b) 46
Solution:

There are 23 pairs of Chromosomes i.e 46 present in somatic cells of Human beings. A Somatic cell is any cell of the body except sperm and egg cells. These cells are diploid, and each set of the chromosome is inherited from each parent.

47. A baby is born as a result of rhythmic contraction of muscles in __________. [RRB Group D 28/09/2018 (Evening)]

Correct Answer: (d) uterus
Solution:

Rhythmic contractions of the uterus lead to the dilation of the cervix. When the cervix (upper end of the birth canal) is sufficiently dilated, the baby travels from the uterus through the birth canal eventually emerging from the vagina.

48. A male human being receives X sperm from his/her _______. [RRB Group D 01/10/2018 (Morning)]

Correct Answer: (b) mother
Solution:

The male, being XY, can generate two types of sperm : half bear the X chromosome, half the Y. If the egg receives another X chromosome from the sperm, the resulting individual is XX, forms ovaries, and is female; if the egg receives a Y chromosome from the sperm, the individual is XY, forms testes, and is male.

49. The human unfertilized egg contains: [RRB Group D 01/10/2018 (Afternoon)]

Correct Answer: (b) one X chromosome
Solution:

We have 23 pairs of chromosomes, of which one pair determines sex. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY).
During fertilisation, the egg is combined with male chromosome, which can either be X or Y. If a combination forms XX pair then offspring will be Female, and if it is ‘XY’ then offspring will be Male.

50. Hydra, starfish, planaria undergo: [RRB Group D 03/10/2018 (Afternoon)]

Correct Answer: (b) regeneration
Solution:

Regeneration: The process by which some organisms replace or restore lost or amputated body parts. Fragmentation - is a type of asexual reproduction in which an organism simply breaks into individual pieces at maturity. Example - Fungi, lichens.
Sporulation - is the generation of spores from vegetative cells in the presence of unfavorable environmental conditions. Examples - Ferns, Fungi, Green Algae. Budding : an asexual reproduction method in which a new organism develops from a bud of an existing organism. Example - Hydra.