explain contraction and abbreviation in punctation 

Dear student,

Kindly refer to the links given below:
https://www.meritnation.com/ask-answer/question/what-is-contraction-pronouns/pronouns/7039495
https://www.meritnation.com/ask-answer/question/what-is-the-meaning-of-abbreviations/articles/4465857
https://www.meritnation.com/ask-answer/question/what-are-certain-abbreviations/nouns/9799859

Regards