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Science · 2024 · 5 marks
CBSE 2024 · Region 3 · Set 3 · Q35
(a)Name any two sexually transmitted diseases.(b)Prenatal sex determination is prohibited by law. Why ?(c)Name any three methods of contraception stating one side-effect of each.OR 35. (a) Name a unisexual and a bisexual flower.(b)Define cross pollination. State how it is carried out.(c)Observe the diagram given below and name the parts marked as 'A' and 'B'.
Mention the function of each of these parts.
(a)
Name any two sexually transmitted diseases.
(b)
Prenatal sex determination is prohibited by law. Why ?
(c)
Name any three methods of contraception stating one side-effect of each.
OR 35. (a) Name a unisexual and a bisexual flower.
(b)
Define cross pollination. State how it is carried out.
(c)
Observe the diagram given below and name the parts marked as 'A' and 'B'.
Mention the function of each of these parts.
Marking-scheme solution
(a) Gonorrhoea, Syphilis, AIDS, Warts
(b) Because child sex ratio is declining/ due to reckless female foeticide.
(i) Oral pills/ Chemical method ; change the hormonal balance of the body.
(ii) Copper - T or loop; irritation of the uterus.
(iii) Surgical method; can cause infections.
(a) Unisexual - Papaya / Watermelon Bisexual - Hibiscus / Mustard
(b) The transfer of pollen grains from anther of one flower to stigma of another flower is called cross - pollination.
Transfer of pollen grains is carried out by some pollinating agents like wind, water and animals.
(c) A → Plumule - Future shoot B → Radicle - Future root
*Refer fig. $\displaystyle 7$•$\displaystyle 9$ Page $\displaystyle 121$ for diagram
Chlor - alkali process;
When electricity is passed through NaCl (aq) it decomposes to form sodium hydroxide./ \(\displaystyle 2 \mathrm{NaCl}+2 \mathrm{H}_{2} \mathrm{O}---\rightarrow 2 \mathrm{NaOH}+\mathrm{Cl}_{2}+\mathrm{H}_{2}\)
X - \(\displaystyle \mathrm{Cl}_{2}\) gas - at anode
\(\displaystyle \mathrm{Y}-\mathrm{H}_{2}\) gas - at cathode
(Bleaching powder)
Emulsification of fats.
Acidic medium has to be made alkaline for the pancreatic enzymes to act.
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CBSE Class 10 Science past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.