I forgot to include the following 4 statements. I hope you can correct them, too. Thank you.

1) Friendship is very important to (also "for") me.
2) In the future I'd like to become a chemist. I want to graduate and go to live abroad, maybe in Asia or America.
3) I've got two brothers; my younger (and not youngst) brother is seven and my older on is seventeen.
4) My favourite food are (?) pizza and chips. My favourite animal is the Panda.

3. younger brother

4. favourite foods are . . .

1) Friendship is also very important for me.

2) In the future, I'd like to become a chemist; I also would like to graduate and live abroad, maybe in Asia or America.
***3) This sentence is confusing as it sounds as if you are either discussing more than two brothers or your seven year old brother is older than your seventeen year old brother (which obviously is inaccurate). Not knowing exactly what you mean to say, I would suggest changing the sentence to: I have two brothers, one is my younger brother and seven years old, and the other is my older brother and seventeen years old.
4) My favorite foods are pizza and chips and my favorite animal is the panda.

I hope this helps.

Certainly! Here are the corrected versions of the statements:

1) Friendship is very important to me.
Correction: Friendship is very important to me.

2) In the future, I'd like to become a chemist. I want to graduate and live abroad, maybe in Asia or America.
Correction: In the future, I'd like to become a chemist. I want to graduate and live abroad, perhaps in Asia or America.

3) I've got two brothers; my younger (and not youngst) brother is seven and my older on is seventeen.
Correction: I have two brothers; my younger brother is seven, and my older one is seventeen.

4) My favourite food are (?) pizza and chips. My favourite animal is the Panda.
Correction: My favorite food is pizza and chips. My favorite animal is the panda.