Questions

United State Library of Congress, Washington D.C.

Caspian Sea (371,000 sq km)

A metaphor is a figure of speech that is used to make a comparison between two things that aren't alike but do have something in common.

In all the given options we have Metaphors.

Sanjay Kothari, Chairman of Public Enterprises Selection Board, has been appointed as Secretary to President-elect Ram Nath Kovind.

Sound is a mechanical vibration and needs a medium for propagation. The higher the density of the medium, the faster the sound travels. So, sound cannot travel through vacuum.

As the sound travels faster in solids than liquids and gases, sound travels faster in the glass than Air and water.

Reliance Industries Chairman Mukesh Ambani overtook China’s Hui Ka Yan to become Asia’s richest person with a total wealth of $42.1 billion. According to Forbes’ real time billionaire’s list, Ambani's personal wealth rose by $466 million in 2017.

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. 

Carbon dioxide is a main greenhouse gas, found in car exhaust pipes.
Methane and nitrous oxide is another type of greenhouse gas.

Oxygen is the only clean gas out there because we need it to survive. Therefore, the only gas that is not a greenhouse gas is Oxygen.