Question

Fill in the spaces a, b, c and d in the following table of contraceptive devices and the methods of contraception

Multiload 375	a
b	Non-medicated IUD
c	Barrier (method) used by females
Progestasert	d

Answer 1

The population of India is growing very fast, the demand for food and space increasing. To keep control of the population growth, contraceptive methods and devices are used. These are used to prevent the fertilization of ovum mechanically or chemically or to prevent their implantation.

Complete answer: If the fusion of male and female gametes can be prevented, the fertilisation can be prevented. And if the implantation of a fertilised ovum is prevented, the pregnancy can be prevented leading towards the birth control.
It is achieved by contraceptive methods and devices. Most usable contraceptive methods are
Intrauterine device (IUD) - A T shaped device inserted into the uterus for birth control. It may be made up of copper like copper T, CuT380, Multiload 375 etc. or a hormonal device containing hormone progestin like Mirena.
Hormonal methods: Injection like Depo-Provera contains progestin or pill contains estrogen and progestin hormones.
Barrier Methods: like condoms.
Emergency contraceptives: these are used to prevent the undesired pregnancy like copper IUD or hormonal pills containing ethinyl estradiol, levonorgestrel or ulipristal acetate etc.
Permanent contraceptives - Vasectomy and Tubectomy.
Thus correct answers are

Multiload 375	The copper bearing IUD
Copper T	Non-medicated IUD
Female Condom or veginal pouches	Barrier (method) used by females
Progestasert	Hormone releasing IUD

Note:
The male produces male gametes or sperm and females produce female gamete or ovum. When the male gamete and female gametes are fused together, they form the zygote. After fertilization in the fallopian tube, the zygote starts dividing and moving towards the uterus. On reaching the uterus, it gets implanted to the uterine wall and develops into the womb where the embryo grows.