Chlorine is used to disinfect water because chlorine chemicals are very effective against bacteria, viruses and fungi that contaminate water. The process of adding chlorine to water is called water chlorination.

We need robots for dangerous, repetitive and high-precision work. Robots perform tasks in hostile environments that are impossible for humans. They also carry out repetitious tasks with speed and accuracy. Without robots, our modern industrialized world would not be possible.

Halley’s comet is famous because it is the only known short-period comet that is regularly visible to the naked eye from Earth and the only comet that might appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061.

The reason is that Kunti had unknowingly asked the Pandavass to share what they had brought on that day. She did not know that Arjuna had won Draupadi in the court of Draupada.

Democracy is considered the best form of government because it improves the quality of decision making, enhances the dignity of citizens and it is an accountable form of government.

Currencies have different values because the values are determined by the forces of demand and supply which varies between countries. If there are more buyers than sellers of a certain currency, its value goes up. The reason behind more buyers may be good economy and development of the country.