Apostrophe- Plural Vs. Possessive

The student's/students were whispering.

Did you see the red leaf's/leaves?f

I can't read the students/student's handwriting.

I saw the cat's/cats kittens.

Which shows the correct use of a possessive apostrophe?

Which shows the correct use of possessive apostrophe?

In the phrase below, is the word "princess" the plural or the possessor?

The princess's shoes

In the phrase below, is the word "paws" the plural or the possessor?

The puppy's paws

Which word is missing a possessive apostrophe in the sentence below?

When I looked out to the ocean, I could see Viking boats with dragons heads approaching.

Which word is missing a possessive apostrophe in the sentence below?

As I walked into the monastery, I could see the monks eating their breakfasts and the look on my brothers face was one of shame.