It's hot outside today.
It's is the contrasted form of it is and its is the possessive form *as it is without an apostrophe*.
For example:
The tree has lost all its leaves.
It's my birthday today.
C: Hucks pap returned
How did Huck like moving back with his Pap?
He enjoyed it, aside from the beatings
How are the townspeople looking for Huck?
shooting cannons
B. Education, healthcare, and social work I think