Questions

Relegate means Assigning an inferior rank or position to. That means, downgrading or pulling down, lower a person.

All other options have words with opposite in meaning.

Hence, Relegate is an English word which is similar in meaning to Downgrade.

Enzymes are protein macromolecules. Enzymes are almost always made of proteins only. Proteins are large biopolymer molecules that are made up of repeating monomer units called amino acids. There are 20 different common amino acids that make up proteins like enzymes. Of these, nine amino acids are essential, which means you must get them from your diet.

Enzymes catalyze chemical reactions in biological systems. This means that they speed up the rate of the reaction.

mercaptans (or thioalcohols) have a foul odour

Ethiopia is the new name of a country which is historically called as Abyssinia.

New name     -      Old name

Namibia        -      South West Africa

Zimbabwe     -      Southern Rhodesia

Thailand        -      Siam.

Currently, the Melbourne Cricket Ground is the world's largest cricket stadium in the world with a total capacity of 100,024. The boundary line of this ground is 85–92 meters from the middle of the pitch which is the highest of all the Cricket grounds around the world. While Kolkata's Eden Gardens is reportedly No. 2 with a capacity of 66,000. 

The Sardar Patel Gujarat Stadium, also known as Motera Stadium getting built in Ahmedabad will accommodate 1.1 lakh cricketing fans inside the stadium overtaking current record-holder Melbourne Cricket Ground .

Cellular respiration is best associated with the organelle Mitochondrion.