Biology
Gaurav and Garima are the children of Mr. and Mrs. Pandey. The children are fraternal twins.
Which of the following options explains the appropriate features of these twins ?
P: Fraternal twins are produced from one zygote which splits after the morula stage and produces two children at the same time.
Q: Fraternal twins must have two opposite sexes, i.e. one boy and one girl.
R: These twins are biologically diorular or dizygotlic.
S: Two eggs are released from ovaries at a time and both get fertilized.
- P and Q
- Q and R
- R and S
- S and P
Related Questions
The canal through which each testis descends into the scrotum just before the birth of a male baby is :
- Acrosome
- Epididymis
- Efferent duct
- Inguinal canal
Given below are the functions of male accessory glands in humans.
(i) Prostate gland pours an acidic secretion into the semen.
(ii) The secretion of bulbo-urethral glands serves as a lubricant.
(iii) The secretion of prostate gland neutralises the alkali in a human vagina.
(iv) The secretion of seminal vesicles serves as a medium for the transportation of the sperms.
Which of the above options are correct ?
- (i) and (ii)
- (ii) and (iii)
- (ii) and (iv)
- (iii) and (iv)
Assertion (A): The placenta is a vital organ during pregnancy, responsible for providing nutrients and oxygen to the developing foetus.
Reason (R): The placenta develops from the fusion of the zygote and the endometrial lining, forming a specialized tissue structure that facilitates the exchange of substances between the maternal and foetal bloodstreams.
- Both A and R are True
- Both A and R are False
- A is True and R is False.
- A is False and R is True.
Assertion (A): Leydig cells produce oestrogen and progesterone.
Reason (R): Leydig cells are also called as interstitial cells which are located as packing tissues between the coils of seminiferous tubules.
- Both A and R are True
- Both A and R are False
- A is True and R is False.
- A is False and R is True.