"What"
The term "very sorry for having done wrong" is a sentence fragment (there is no subject to form a complete sentence). The abstract noun in the sentence fragment is "wrong" a word for a concept.
The word "were" in the sentence should be "was" instead. The simple subject of the sentence is "packet", a singular noun that requires a singular verb form. "Chips" is merely the object of a preposition and not the simple subject of the sentence, although it is part of the complete subject.
The sentence is grammatically incorrect. It should be structured as "Taking a psychology test," with the subject preceding the action.
It is Platypus is the complet subject. If you get it wrong, im sorry. Im only a girl and in 5th
The subject of the sentence is "you"
The sentence should be "Bill and he had about 600 dollars between the two of them." "Him" is the object form, while "he" is the subject form, which is correct in this case as "he" is the subject of the verb "had."
A subject in a sentence is who, what, or where the sentence is about.
There is a debate in current linguistics (but most of the evidence indicates that you can't go wrong by thinking of the subject as an empty placeholder for a second-person pronoun (you).
The subject is who or what the sentence is about.
You is the subject of that sentence.
"That was wrong" is a grammatically correct sentence.
There is nothing wrong with that sentence.