between use only two person, things ,place and among More than two ......

what are you doing today?...

my mother is housewife....

pronoun use in place of noun ...for exmpl...1 ram is a student, he(pronoun) is going to school.

...on the earth

i am from Ludhiana

1first right because principles means... rule ,theory, idea ,concept and principal means.. chief main (( I'm sorry 1 sentence in " may in place of my is my " my mistake... sorry))

it's singular form.. piece of information, piece of bread ,piece of paper ......I think there are after Do not use " s / es "

i think...I study in 4th...( standard/ class...)

my rank in city