Questions

In a chemical reaction, substances (elements or compounds) called reactants are changed into other substances (compounds or elements) called products. Hence, reactants are those which start the chemical reaction.

For example:

1. In the burning of natural gas, methane (CH4) and oxygen (O2) are the reactants in the chemical reaction. are the substances formed by a chemical reaction. In the burning of natural gas, carbon dioxide (CO2) and water (H2O) are the products formed by the reaction.

2. H2+O2 ----> H2O

Here H2 & O2 are called Reactants and H2O is called Product.

Countless potential customers in retail shops go unnoticed every day. It is often this attitude of indifference that leads people to shop at other places. Make sure that you have a candidate that will meet and greet your customers. Interviewees, let your personality shine here. Let your interviewer know that you are not afraid to introduce yourself to customers, and that you will not be hiding in the back restocking something.

The F1, F2 to F12 keys that are found on the top row of most computer keyboards are called as Function Keys. Unless you've witnessed the evolution of computers from their early days, you probably don't know why they were invented and for what.
Function keys were used by various computer programs to fulfill various functions.

F12 - It is used by many web browsers to open the developer tools.

Designers have to either combine marketing intelligence and artistic vision themselves, or be able to delegate business duties to hired specialists, agents, etc. while they focus on the art.

Weight is mass x g. Since mass is constant and g is only 16thof that on the earth. The weight on the moon is only 16th of that on the earth. 

Therefore 2N i.e (b) is the answer.