Human Body Systems

We are born with ____ bones.

• 300

• 206

The adult skeleton has ____ bones.

• 300

• 206

The largest bone in the human body is the ___.

• stapes

• femur

There are over ____ muscles in the human body.

• 650

• 880

Muscles that we control are ____ muscles.

• involuntary

• voluntary

Muscles that we do not control are ____ muscles.

• involuntary

• voluntary

____ muscles are found in the heart.

• cardiac

• skeletal

____ muscles are attached to our skeleton and allow our bodies to move.

• cardiac

• skeletal

The main organs of the respiratory system are the ____.

• large intestines

• lungs

We breathe in oxygen and breathe out ___.

• carbon dioxide

• oxygen