Equivalent acidity of Ammonium sulphate fertilizer

Perpetual

When something is unclear

Choose the word opposite in meaning to the given word:

Benevolent

 Fill in the blanks with the appropriate antonym of the word in Italic from the options given:

Read each sentence to find out whether there is any grammatical error in it. Mark the part with the error as your answer. 

Swindle

Select the most appropriate ANTONYM of the word ‘SINKS’ from the given sentence.

A person who collects and studies stamps.

One who knows everything