Questions

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.

Sea appears blue in colour due to the scattering of the rays when they hit water molecules

Sir Benegal Narsing Rao (B N Rau), was the Constitutional Advisor to the Constituent Assembly. He was an Indian civil servant, jurist, diplomat and statesman known for his key role in drafting the Constitution of India.

He was also India's representative to the United Nations Security Council from 1950 to 1952.

First Generation  Vacuum Tubes (1940-1956)

The first computer systems used vacuum tubes for circuitry and magnetic drums for memory

Peru is a country in South America. Lima is the capital city of Peru. Sol is the currency of Peru.

Woodland tribes lived in wigwams and longhouses. Wigwams are round, wooden-framed structures, covered in bark. Only one familylived in a wigwam. Longhouses are made the same way as wigwams except they are rectangular, instead of round. They have a long hallway with rooms on both sides. Several related families shared a longhouse.

Longhouse Commonly lived in by entire Native American families in the Eastern Territories pre-colonization.