Questions

How CNG is a cleaner fuel?

I. It produces oxides of Sulphur and Nitrogen in very small amounts.
II. It makes environment less polluted.
III. It emits less greenhouse gases.

Which Indian Chief Minister's father was a 'Maharaja' ?

Which of the following events is not related to the era of Warren Hastings?

When was Postal Index Number (PIN) or PIN Code introduced in India?

Which is the most polluted city in the world, according to Air Quality Index 2018?

Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.

Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as bitumen, asphalt and natural gas. Mineral oil originates from the carcasses of tiny animals and from plants that live in the sea. Over million of years, these dead creatures form large deposits under sea­bed and ocean currents cover them with a blanket of sand and silt. As this material hardens, it becomes sedimentary rock and effectively shuts out the oxygen, thus preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rocks become thicker, and heavier. Their pressure produces heat, which transforms the tiny carcasses into crude oil in a process that is still going on today.

Sedimentary rocks leads to the formation of oil deposits because

Tennis rackets and ballpoint pens are

The goal of a command economy is to