Science [2 Mark Questions]

Thyroxine hormone needs Iodine for its synthesis. If its amount will be low in the diet then the hormone production will lower down causing hypothyroidism and goitre.

i. Harmful effects of plastic bags :
a. Plastics do not undergo degradation, thus stay in soil for many years. This may affect the soil fertility and degrades the soil quality.
b. When plastic artifacts enter the drainage and sewerage system, they block the pipes and drains causing water logging.
c. Littering of plastics in open spaces creates unhygienic conditions, as it acts as breeding ground for insects and mosquitoes.
We can reduce the use of plastic bags and carry jute bags and paper bags to carry items from the market.
ii. Measures taken for proper disposal of waste produced at our homes are :-
a. Prepare a compost pit for kitchen wastes.
b. Safe disposal of plastic bags.
c. Segregation of biodegradable and non-biodegradable wastes.
d. Fruit peels can be placed near trees or plants, which on decomposition will enrich the soil with nutrients.
e. Recycling of paper wastes.

Barrier method : In this method, the fertilisation of the ovum and the sperm is prevented with the help of barriers such as a condom.
Implants and surgical methods : Contraceptive devices, such as a loop and a copper-T rod, are placed in the uterus to prevent pregnancy. However, they can cause side effects to the uterus.
Some surgical methods such as vasectomy (blocking of the vas deferens in the male body to prevent the transfer of sperms) and tubectomy (blocking of fallopian tubes in the female body to prevent the egg from reaching the uterus) can also be used to block the gamete transfer.