Questions

An Umbrella.

Yes, when it is open it can't be fit under a chimney but when it is closed it can be fit down a chimney.

A search engines are a software systems used for searching about any information in the world on the web.

Search engines like Google, Bing, Internet explorer, Yahoo, etc... functions by providing relevant search results for the keywords user searches. 

Hence, the given statement is TRUE.

Jean Piaget was a cognitive psychologist who identified four stages of development: the sensorimotor stage from birth to 2 years, the preoperational stage from age 2 to age 7, the concrete operational stage from age 7 to 11, and the formal operational stage from age 11 to adult. He identified milestones that occur at each stage.

According to Piaget, the main task of the sensorimotor stage is for the child to learn the concept of object permanence, use senses and motor skills to understand the world.

The process by which bacteria convert nitrogen gas (N2) into ammonia (NH3) is called Nitrogen Fixation.

The conversion of nitrogen from one form to another in the nitrogen cycle is carried out primarily by Nitrogen Fixing Bacteria such as Azotobacter.

Firstly, I focussed on "If you remove my 1st & 2nd letters, you can't see me". The first thing that comes to mind which we can’t see is the "AIR".

So now, what 4 letter words can be formed ending with "AIR"? Think of all the words from A to Z, considering which one lies above you. That is how we get to "HAIR".

Now, which 5 letter word can be formed ending with "HAIR"? Starting with A to Z, we reach "CHAIR" and also, it lies below us.

And the required answer is "CHAIR".

M=P(1+i)^n

Speed in a given direction is called Velocity.