The backbone has a canal running through it lengthwise, in which lies the spinal cord.
6.

The trunk is hollow, and has two chambers, one called the cavity of the chest, and the other the cavity of the abdomen.
7.

The chest contains the two lungs and the heart.
8.

The abdomen contains the stomach, liver, and many other very important organs.
9.

Is it not our duty to take good care of our bodies as we would of some nice present from a friend?
.