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प्रश्न
Give scientific reasons: Mature erythrocytes in humans lack nucleus and mitochondria
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उत्तर
In case of fertilisation of the ovum by a sperm, the corpus luteum persists and continues to secrete progesterone in the body thus maintaining its high levels. The presence of progesterone prevents the maturation of another ovum, thus temporally stopping the menstrual cycle.
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संबंधित प्रश्न
What are the functions of testes in the human male reproductive system?
What are sexually transmitted diseases?
If a woman is using copper-T for contraception, will it protect her from sexually transmitted diseases?
Write the function of the following part in a human female reproductive system:
Fallopian tube
Why is it an advantage for the testes to be situated in the scrotal sac outside the main body cavity? Can you think of one disadvantage?
What is ovulation?
X and Y are two human beings. The organ A in the reproductive system of X releases a mature gamete B once a month which goes into a tube-like structure C through a funnel-like opening. The organ D in the reproductive system of Y makes and releases gametes E which pass through a duct F and are introduced by an organ of Y, into the body of X. B and E fuse together in C to form a new cell G. The cell G divides repeatedly to form a ball of cells H which gets embedded in the lining of organ I of reproductive system of X where it grows and develops into a baby.
(a) Name (i) organ A, and (ii) gamete B.
(b) Write two names of tube-like structure C.
(c) Name (i) organ D, and (ii) gamete E.
(d) Write two names of duct F.
(e) Name (i) cell G (ii) ball of cells H, and (iii) organ I.
(f) Out of X and Y, which one is (i) male, and (ii) female?
Define the term puberty.
The vagina is a muscular tube.
Freshly released human egg has ______.
