Identify the preposition in the following sentence:

Humans' original source of fire was probably lightning.

Identify the preposition in the following sentence:

A fire started when a tree was struck by lightning.

Identify the preposition in the following sentence:

The shelter was often deep within a cave.

Identify the preposition in the following sentence:

All fires that the tribe needed probably were started by these coals.

Identify the preposition in the following sentence:

If the tribe moved, the keeper of the fire may have carried the coals.

Identify the preposition in the following sentence:

The attendant probably stayed near the fire and kept it going.

Identify the object of the preposition in the following sentence:

Humans first learned how to make their own fire during the Stone Age.

Identify the object of the preposition in the following sentence:

Janice and Carla spent the day at the mall.

Identify the object of the preposition in the following sentence:

The children were charmed by the magician's tricks.

Identify the object of the preposition in the following sentence:

We visited the Royal Ontario Museum in Canada.