| A | B |
|---|
| ribs | a group of long, curved bones that support and protect the chest |
| blood | the liquid that is moved by the heart through the body in blood vessels |
| bone | a hard, white piece of the skeleton |
| circulatory system | the body system that moves blood throughout the body |
| brain | the control center of the nervous system |
| skull | the main bone structure of the head |
| carbon dioxide | a clear gas that is given off as a waste product during breathing |
| spine | a column of bones that provides the main support for the body; the backbone |
| cells | the tiny parts that all plants and animals are made of |
| digestive system | the body system that breaks down food to give the whole body the nutrients it needs |
| skeletal system | the body system that provides a sturdy frame to support all other body systems |
| excretory system | the body system that removes waste and poisons from the body |
| heart | the organ that pumps blood throughout the body |
| kidneys | a pair of excretory organs that filter waste products from blood |
| lungs | two spongy organs that bring oxygen to the blood and remove carbon dioxide from the blood |
| muscle | body tissue that lets the body move by contracting and relaxing |
| muscular system | the body system that allows body parts to move |
| nervous system | the body system that gathers information from the senses and controls thinking and behavior |
| oxygen | the invisible, odorless gas that makes up part of the air humans must breathe to live |
| respiratory system | the body system that controls breathing by inhaling oxygen and exhaling carbon dioxide |
