List two reasons that make copper releasing IUDs as effective contraceptives.
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Solution and Explanation
1. Toxic to sperm:
- The copper released by the IUD creates a toxic environment for sperm, impairing their motility and ability to fertilize the egg.
2. Prevention of implantation:
- Copper IUDs alter the lining of the uterus, making it inhospitable for a fertilized egg to implant and grow, thus preventing pregnancy.
Top Questions on Reproductive Health – Problems And Strategies
Student to attempt either option-(A) or (B):
(A) Study the given diagram showing the sectional view of a seminiferous tubule.
Answer the following questions:- [(i)] Label A, B, C and D in the figure.
- [(ii)] What will be the number of chromosomes in secondary spermatocyte and spermatid respectively?
- [(iii)] Explain the terms — Spermiogenesis and Spermiation.
OR
(B) Study the figures given below showing initial stages in the formation of female gametophyte and answer the questions that follow.
- [(i)] Identify (P) and (Q).
- [(ii)]
- [I.] What kind of division does cell (P) undergo to form (Q)?
- [II.] How many (Q) cells form the embryo sac? What is the name given to such kind of development?
- [III.] How many free nuclear mitotic divisions will the functional megaspore undergo to form the embryo sac?
- [IV.] Describe the structure of a mature female gametophyte.
- CBSE CLASS XII - 2025
- Biology
- Reproductive Health – Problems And Strategies
- A village health worker was taking a session with women. She tells them that one has to be careful while using oral pills as a method of birth control. Wrong usage can actually promote conception.
(A) Analyse the statement — oral pills need careful usage, as wrong usage can promote conception. Compare merits and demerits of using oral pills and surgical methods of birth control.
(B) Village women are confused as to how a thin metallic copper loop can prevent pregnancy. Explain the mode of action of IUDs. Give two points.- CBSE CLASS XII - 2025
- Biology
- Reproductive Health – Problems And Strategies
- Student to attempt either option (A) or (B):
(A) “A fully developed foetus initiates its delivery from the mother’s womb.” Explain.
OR
(B) Give reasons for the following:- Why can a woman generally not conceive a child after 50 years of age?
- Polar bodies are formed during oogenesis and not during spermatogenesis.
- CBSE CLASS XII - 2025
- Biology
- Reproductive Health – Problems And Strategies
- Pick up the hormone releasing intrauterine device.
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- Zoology
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- Which two main inflammation-causing chemicals are produced by the mast cells in such an immune response?
- CBSE CLASS XII - 2025
- Biology
- Reproductive Health – Problems And Strategies
Questions Asked in CBSE CLASS XII exam
- A point source of light in air is kept at a distance of 12 cm in front of a convex spherical surface of glass of refractive index 1.5 and radius of curvature 30 cm. Find the nature and position of the image formed.
- CBSE CLASS XII - 2025
- Ray optics and optical instruments
- Two slits 0.1 mm apart are arranged 1.20 m from a screen. Light of wavelength 600 nm from a distant source is incident on the slits.
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- Two infinitely long straight wires ‘1’ and ‘2’ are placed \(d\) distance apart, parallel to each other, as shown in the figure. They are uniformly charged having charge densities \(\lambda\) and \(-\frac{\lambda}{2}\) respectively. Locate the position of the point from wire ‘1’ at which the net electric field is zero and identify the region in which it lies.
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- Electrostatics
Standard electrode potential for \( \text{Sn}^{4+}/\text{Sn}^{2+} \) couple is +0.15 V and that for the \( \text{Cr}^{3+}/\text{Cr} \) couple is -0.74 V. The two couples in their standard states are connected to make a cell. The cell potential will be:
To calculate the cell potential (\( E^\circ_{\text{cell}} \)), we use the standard electrode potentials of the given redox couples.
Given data:
\( E^\circ_{\text{Sn}^{4+}/\text{Sn}^{2+}} = +0.15V \)
\( E^\circ_{\text{Cr}^{3+}/\text{Cr}} = -0.74V \)- CBSE CLASS XII - 2025
- Electrochemistry
A carpenter needs to make a wooden cuboidal box, closed from all sides, which has a square base and fixed volume. Since he is short of the paint required to paint the box on completion, he wants the surface area to be minimum.
On the basis of the above information, answer the following questions :
Find a relation between \( x \) and \( y \) such that the surface area \( S \) is minimum.- CBSE CLASS XII - 2025
- Relations and Functions