Peter didn't know was his.
whichever
which
whomever
who

which...  it is the only one that makes sense in the sentence.

what is a theme?

ans: the implicit idea of a written work of literature is called a theme.

so, the only theme of "birdfoot's grampa" by joseph bruchuc is that as a human being one should always remember the value of every life on earth.

the grampa is stopping the car again and again to save those little toads from washing away in the heavy rain is an act of kindness and humanity.