WhatOPTION A: How do you think differentiatesadults and children differ? OPTION B: What are the main differences between adults and children?¶
OPTION C: In what ways do adults fromand children differ?

Many other options also exist . . . .

BETTER: I don't know thehow to answer to this question precisely.

I think adults are the people who can take responsibility for what theiry doing and saying.

SUGGESTION: Add this sentence to the previous sentence --
By contrast, children cannot.

It doesn't matter abouHowever, the main issue is not age or ability.

SUGGESTION: Add this sentence to the previous sentence --
The main issue is responsibility.

MY GUESS: I would like to be a generous and responsible person in the future.

I think adults are the peopleones who can take responsibility for what theiry doing and what they saying.

“People” is ok but you might be more likely to use “ones” in this context. You would say you take responsibility for “what you do” and “what you say” and this apples to most other verbs (although there are probably some exceptions to this like everything else in English!)

It doesn't matter about age or ability.

This is fine, particularly when it is not certain who you’re referring to, but you could say “it doesn’t matter about your/their age or ability” to make it flow a bit better and make it sound a bit more natural.

I would like to be a generous person in the future.

To make it sound a little less formal (if that’s the tone you’re intending), you could say “I’d” instead of “I would”.

I think adults are the people who can take responsibility for what theiry doing and saying.

ItAge or ability doesn't matter about age or ability.