AIIMS Zoology Human Reproduction Class 12 Questions

Choose the correct option

Choose the correct one

The statement given in both assertion and reason are wrong. Selaginella and Salvinia do not produce spores that cannot be differentiated by sex.

The process of delivery of foetus (childbirth) is called parturition. Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induces mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscles and causes stronger uterine contractions which in turn stimulate further secretion of oxytocin.

Correct hormonal sequence in the case of menstruation as

The 'cells of Rouget' are

Choose the correct statement.

Which of the following statements is correct?

Assertion : Corpus luteum is produced by Graafian follicle after ovulation. Reason : It secretes estrogen which is necessary to maintain pregnancy.

What do A, B, C and D represent?

Which animal has the longest gestation period?

Assertion: Parturition is induced by neural signal in maternal pituitary. Reason: At the end of gestation period, the maternal pituitary release prolactin which causes uterine contractions.

In humans at the end of first meiotic division, the male germ cells differentiate into the

Assertion: Amniocentesis is a process of foetal sex determination. Reason: Metabolic errors and other diseases can be diagnosed prenatally by this process.

Assertion: Mammalian ova produces hyaluronidase. Reason: The eggs of mammal are microlecithal and telolecithal.

Which of the following is true regarding sperm?

A cross section at the midpoint of the middle piece of a human sperm will show

Which one of the following events is correctly matched with the time period in a normal menstrual cycle?

Both corpus luteum and macula lutea are:

The phase of menstrual cycle in humans that last for 7-8 days, is:

Which one of the following statements with regard to embryonic development in humans is correct?

Assertion : Holoblastic cleavage with almost equal sized blastomeres is a characteristic of placental animals. Reason : Eggs of most mammals, including humans, are of centrolecithal type.

An oocyte is released from the ovary under the influence of LH