Questions

The answer is EDUCATION

4,5,6 make up the word cat,

7th is 'i' which means me,

3rd letter is 'u' which mean you,

2,8,9,1 make up the word done, which means completed

and nobody can read without education.

A tertiary consumer is an animal that obtains its nutrition by eating primary consumers and secondary consumers.

Usually tertiary consumers are carnivorous predators, although they may also be omnivores, which are animals that feed on both meat and plant material.

Tertiary consumers often occupy the top trophic level, and so are predated by no other animals; in this case they are called "apex predators". However, when they die their bodies will be consumed by scavengers and decomposers.

A place where monks live as a secluded community is Monastery.

A Jig saw puzzle pieces are in different colors which have different shapes. 

You can put it anywhere you like but there is only one right place for it to be fit in it.

It is a Postbox or a Mailbox which contains thousands of letters or mails or messages.