Questions

First Generation  Vacuum Tubes (1940-1956)

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

Dipsomania is one word substitute for Irresistible craving for alcoholic drinks.

Capital of jamica is Kingston

Here in the given options, The girl, whom you have met yesterday is my sister is the sentence which has relative pronoun.

The pronoun which is used to connect a clause or phrase to a noun or pronoun is called as relative pronoun.

The most common relative pronouns are who, whom, whose, which, and that. Sometimes when and where can also be used as relative pronouns.

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.