Questions

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.

The only gem of world made of a single element is Diamond.

The given statement that "Most pathogenic bacteria are thermophiles" is FALSE.

A UPS (Uninterruptible Power Supply) is a device that provides battery backup when the electrical power fails or drops to an unacceptable voltage level.

Small UPS systems provide power for a few minutes; enough to power down the computer in an orderly manner, while larger systems have enough battery for several hours.

Coal is chemically complex fuel. Whenever it is burned, gases are given off and particles of ash, called "fly ash," are released. Release of sulfur from burning into the air. The sulfur in coal combines with oxygen to form sulfur dioxide, which can be a major source of air pollution if emitted in large enough quantities. This stuff comes back as acid rain when it attaches itself to a raindrop. 

Today, many of the effects of coal burning have been reduced significantly or eliminated. This is super-nasty and is only stopped by buying low-sulfur coal from Montana or Wyoming. The eastern power plants have to pay to move the coal from out west and this increases the price of power production.