Home
Class 12
BIOLOGY
Read the following statements about mens...

Read the following statements about menstrual cycle and select two correct statements:
(i). Lack of menstruation may be indicative of pregnance
(ii). The changes in the ovary and the uterus are induced by changes in the lveles of ovarian hormones only
(iii). LH surge induces ovulation
(iv). If fertilisation occurs, corpus luteum degenerates immediately

A

(i) and (ii)

B

(ii) and (iii)

C

(i) and (iii)

D

(ii) and (iv)

Text Solution

Verified by Experts

The correct Answer is:
C
Lack of menstruation may be indicative of pregnancey. During preganance, the levels of estrogen and progesterone are high in the blood. Which are required for the maintenance of uterus and thus, mensturation does not occur. On `14^(th)` day of the menstrual cycle. there is rapid increase in LH (called LH surge), that induces ovulation. The changes in the ovary and the uterus are induced by change in the level of ovarian hormones and pituitary hormones, if fertilisation occurs, corpus luteum degenerates by `16^(th)` week of pregancy.
Doubtnut Promotions Banner Mobile Dark
|

Similar Questions

Explore conceptually related problems

Read the following statements about the reproductive cycles in mammals and select the correct ones. (i) Oestrous cycle occurs in primate mammals. (ii) In species with oestrous cycle, females are generally sexually active during oestrous phase. (iii)Both the cycles show monthly recurrence.

Read the following statement regarding bryophytes and select the correct answer. (i). Bryophytes lack true roots, stem and leaves. (ii). The main plant body is haploid (iii). Sex-organs are unicellular and non-jacketed (iv). Fertilisation produces an embryo inside the water.

Read the following statements about asexual reproduction and select the correct ones. (i) It involves a single parent. (ii) It is slower than sexual reproduction. (iii) It produces progeny that are genetically identical with the parent but not with one another. (iv) The progeny of asexual reproduction can be termed as clones.

Read the given statements about algae and select the correct option: (i). Plant body is thalloid (ii). They are largely aquatic. (iii). Reproduction occurs by vegetative, asexual and sexual methods. (iv). Chlamydomonas, volvox and Ulothrix are the multicellular algae.

Read the following statements about cell division and select the correct ones. (i) M phase represents the phase when actual cell division occurs and I phase represents the phase between two successive M phases. (ii) In the 24 hours average duration of cell cycle of a human cell, cell division proper lasts for only about an hour. (iii) M phase constitutes more than 95% of the duration of cell cycle.

Read the following statements and select the correct ones. (i) Vaccine is a preparation (or suspension ) of a dead/attenuated pathogen of a disease which on inoculation ( or injection ) into a healthy person, provides temporary/permanent active immunity by inducing antibodies formation. (ii) Immunisation is the process by which the body produces antibodies against the vaccine preventable diseases through administration of specific vaccines. (iii) The principle of immunisation or vaccination is based on the property of 'memory' of the immune system. iv) If a person is infected with some deadly microbes to which quick immune response is required; in that case, we need to directly inject the performed antibodies or antitoxins e.g., in case of tetanus.

Read the following statements and select the option which identifies the incorrect ones. (i) Potato spindle tuber disease and Chrysanthermum stunt disease are caused by viroids. (ii) T_(4) bacteriophage exhibits lytic cycle. (iii) Retroviruses have two copies of ssRNA. (iv) Interferous which prevent viral multiplication are glycolipid particles.

some important events that occur during the menstrual cycle are given below. Arrange the events in a proper sequence and select the corrrect option. (i). Proliferation of endometrial wall (ii). LH surge (iii). Secretion of estrogen (iv). Secretion of progesterone (v). Ovulation (vi). Growth of corpus luteum (vii). Degeneration of corpus luteum (viii). menstruation

Study the following statements and select the correct option. (i) Tapetum nourishes the developing pollen grains. (ii) Hilum represents the junction between ovule and funicle. (iii) In aquatic plants such as water hyacinth and waterlily, pollination occurs by water. (iv) The primary endosperm nucleus is triploid.

Which of the following statements about enzymes are correct ? (i) Enzymes do not alter the overall change in free energy for a reaction. (ii) Enzymes are proteins whose three dimensional energy. (iii) Enzymes speed up reactions by lowering activation energy. (iv) Enzymes are highly specific for reactions. (v) The energy input needed to start a chemical reaction is called activation energy.

Home
Profile