Railway Science (Biology-Reproduction in Animals)

Total Questions: 50

31. What did Mendel discover about the factors that influence heredity? [RRC Group D 05/09/2022 (Morning)]

Correct Answer: (a) A pair of factors in sexually reproducing organisms defines their characteristics.
Solution:

Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance which consist of law of Dominance, law of segregation, law of Independent assortment.
He deduced that genes that come in pairs are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits.

32. All of the following statements about usage of contraceptive devices are true except one. Select the INCORRECT option. [RRC Group D 05/09/2022 (Afternoon)]

Correct Answer: (d) They have no side effects.
Solution:

Contraception - An artificial method or technique, mainly used to prevent pregnancy as a consequence of sexual intercourse.They have some side effects too. Method of contraception - birth control pill, hormonal contraception, condoms.

33. Genes control traits through the activity of _______. [RRC Group D 08/09/2022 (Evening)]

Correct Answer: (d) hormones
Solution:

Gene - Basic structural and functional unit of heredity. Genes are capable of controlling traits. Traits - Certain qualities or characteristics that distinguish one individual from another. The word “gene” was coined by Johannsen. Father of Genetics - Gregor Johann Mendel.

34. In which of the following classes does temperature determine the sex in some species? [RRC Group D 09/09/2022 (Morning)]

Correct Answer: (d) Reptiles
Solution:

All reptiles (or at least reptile species that have no sex chromosomes) display temperature - dependent sex (TDS) determination, rather than genetic sex determination. TSD is observed in many fish, all crocodilians, many turtles, and lizards. Mammals- Have milk-producing mammary glands. Amphibian - These can live both on land and in water. Aves - They are known as birds.

35. The figure given below shows the sectional view of the human female reproductive system. Identify the option stating correct functions of the labelled parts A and B. [RRC Group D 09/09/2022 (Evening)]

Correct Answer: (b) A - Implantation and development of embryo, B - Fertilisation of egg
Solution:

Ovaries : The female reproductive system is made up of several organs including the vagina, uterus, fallopian tubes, cervix, and ovaries. Two ovaries are located on either side of the uterus.
Ovaries are small, oval-shaped glands that are responsible for the production and release of eggs. Fallopian Tubes : One of two long, slender tubes that connect the ovaries to the uterus.
Eggs pass from the ovaries, through the fallopian tubes, to the uterus. Vagina : It is a closed muscular canal that extends from the outside of the female genital area (vulva) to the neck of the uterus (cervix).
Ovulation : Process of releasing the eggs from the ovaries. Menstrual cycle : It is a series of physiological changes that occur in a woman's body over approximately 28 days.
It involves the monthly shedding of the lining of the uterus (endometrium) and the release of an egg (ovulation) from the ovary in preparation for pregnancy.

36. The process by which an organism begins life as a female and then transforms into a male is known as: [RRC Group D 12/09/2022 (Evening)]

Correct Answer: (d) Protogyny
Solution:

Protogyny - The condition in which the female reproductive organs (pistil) matures before the male reproductive one (anthers). This condition is seen in Banana, Fig, Plum etc.
The condition in which the male reproductive organs of a flower matures before the female one is known as protandrous/protandry. The coconut palm is protandrous and male flowers open immediately after splitting the spadix.

37. _______are responsible for the determination of sex. [RRC Group D 14/09/2022 (Morning)]

Correct Answer: (c) Allosomes
Solution:

Allosomes (sex chromosome, one pair in body) are the genes involved in sex determination. Humans have 23 pairs (46 chromosomes) chromosomes. Autosome (22 pairs) is not a sex chromosome.
Pleiotropic gene is a single gene that controls more than one trait. Germ cell is a cell that develops into a reproductive cell, which is an egg in females and a sperm in males.

38. The different points mentioned below constitute Reproductive Health. Select the INCORRECT option. [RRC Group D 14/09/2022 (Morning)]

Correct Answer: (c) Determining the sex of the unborn child
Solution:

Reproductive Health Problems : Deformities, Overpopulation, Sexually Transmitted Diseases, Ill health of both mother and her baby, early marriages before attaining puberty, an increased mortality rate of both mothers and Infants.

39. Which of the following contraceptive methods is useful for controlling both unwanted pregnancies and STDs? [RRC Group D 15/09/2022 (Evening)]

Correct Answer: (d) Condom
Solution:

Condom : They are accustomed to prevent unwanted pregnancies still as sexually transmitted diseases (STDs) and Human Immunodeficiency Virus (HIV). Surgical method - Laparoscopy is often used during surgery to look inside the body and avoid making large incisions. oral contraceptive pills - A pill used to prevent pregnancy.

40. Which of the following statements are correct? [RRC Group D 18/09/2022 (Morning)]

(A) All children will inherit an X chromosome from their mother.
(B) A child who inherits an X chromosome from her mother will be a girl.
(C) Women have a perfect pair of sex chromosomes; both are called X.
(D) A child who inherits a Y chromosome from his father will be a boy.

Correct Answer: (d) A, C and D
Solution:

Chromosomes are thread-like structures located inside the nucleus of each cell. The first 22 pairs of chromosomes are called autosomes. The 23rd pair of chromosomes are known as the sex chromosomes, because they decide if you will be born male or female. Females have two X chromosomes, while males have one X and one Y chromosome. Male (XY), Female (XX).