Sadness, sorrow, mixed emotion, death of beauty, what a notion
Crowning death, avenging, retaliation, taking back obliteration
Explanation:
A sentence, because it has a subject and verb( well technically a helping verb-are)
I guess formal and informal refer to two types of essay - you can write a formal essay where you avoid conversational language and such and where you need to be very professional, or you can write informally where you don't have to think about such things, it is very casual.
A direct object, hope I helped! ^-^