Questions

A Mirage is a naturally occurring optical phenomenon due to unequal heating of different parts of the atmosphere in which light rays bend to produce a displaced image of distant objects or the sky.

A river which can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps.

In all plants and animal cells chromosomes are located in the Nucleus of the cells.

The Chromosomes are thread like structures present in the nucleus of the cells which are made up of proteins and a single molecule of DNA.

Their function is to carry the characteristic features of parent cells to daughter cells. 

Humble means not having or showing any feelings of superiority, self-assertiveness, or showiness.

Humble means in a modest, lowly and down-to-earth manner. Not in a aggressive, bold, self confident manner.

Hence, in the given options Bold is an antonym of Humble.

AIDS: The term means Acquired Immunity Deficiency Synodrome. The virus attacks the T cells of the (white corpuscle type) blood and destroys them.

In making jewels, gold is usually mixed with copper to make it little hard.