É só ler com atenção, e, se você leu o livro, vai saber de cara, boa sorte mano :)
The Relative Clause is “who are five in number”. It is a type of dependant clause (it need the main clause in order to convey its meaning properly) that has the same function of an adjective; that is to say, it modifies a noun “friends”.
Answer:
Yes it's possible but It would sound better If you said, positive and negative emotions.
Explanation:
Desirable and undesirable can have conflicting meanings I.e desirable is what you like and undesirable is what you don't like but you can desire something negative or have something good that's undesirable to you.
