Find out the odd word/letters/number/number pair from the given alternatives.

Ensure a regular market?

What country is called the patient of Europe?

In which city was the first metro rail service started in India?

A sentence/a part of the sentence is underlined. Four alternatives are given to the underlined part which will improve the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the button corresponding to "No improvement".
The boys absented themselves for two days. 

Arrange the following words in logical order -

1. Embryo 2. Child 3. Child 4. Adult 5. Youth

Canals are the most irrigated in the state-

What is data in a computer?