Questions

The foods that are good source of fat and incredibly healthy to the body ar fatty fish, eggs, nuts, cheese, avocados, dark chocolates, etc...

The main source of organic matter in soil is the plant and animal tissue that decompose at each level of breakdown.

An ionic bond is formed between two molecules when transfer of valency electrons take place between them. 

Isotopes are atoms of the same element that have different mass numbers.

Example : Hydrogen, Deutirium and tritium all these have different mass but same atomic numbers.

'and made India' should be used to make the sentence grammatically correct. You use 'made' when referring to things already done in the past.'Make' is present and its continuous its still been done unlike 'made' which refers to what has been done

A posted speed limit of 55 mph means that we can drive at a speed of 55 miles per hour(mph) under good conditions in that area. We cannot that speed limit in that area.