CBSE Class 10 Science 2020 · Paper 31/2/1 · Question 28(a)

(a) The three categories are barrier methods (for example, the condom, which keeps sperms from reaching the egg); chemical methods (oral pills, which change the hormonal balance so that no egg is released, and vaginal pills or creams, which kill sperms); and surgical methods (vasectomy, in which the vas deferens is blocked, and tubectomy, in which the oviducts are blocked). (b) Prenatal sex determination was being misused for female foeticide, the abortion of female foetuses, because of which the child sex ratio has been declining at an alarming rate in some sections of society; the law was made to stop this misuse. Its benefit in the long run is that a balanced female-male sex ratio is maintained, which a healthy society needs. (c) Bacterial infections: gonorrhoea and syphilis. Viral infections: warts and HIV-AIDS.