The body absorbs nutrients through the ​ (a)   system.

The ​ (b)   system delivers the nutrients to the body's cells.

The female ​ (a)   system produces eggs and nurtures the baby during development.

The ​ (b)   system produces the hormone oxytocin to start contractions before birth.

The ​ (c)   system receives the oxytocin signals, and starts contractions that lead to childbirth.

Bacteria, viruses, and some eukaryotes are considered ​ (a)   that can make you sick.

Naturally occurring poisons that make you sick are called ​ (b)   .

White blood cells are made in the bone marrow, and fight off diseases through the ​ (a)   system.

Red blood cells are made in the red bone marrow, and are part of the ​ (b)   system.

The largest organ in your body is the skin, and it is part of the ​ (a)   system.

Sweat comes from glands in your skin, and are considered waste from the ​ (b)   system.

Tendons connect bones in the ​ (a)   system to the ​ (b)   system that allows for movement.

When you sneeze, your ​ (a)   system is removing pathogens and allergens from your nose, which assists your ​ (b)   system in fighting off diseases.

The ​ (a)   system relies on neuron signals in the layers of your ​ (b)   system to sense pressure, pain, heat, cold, sharp, and smooth dangers in your environment.

Urine is stored in a smooth muscle vessel that is part of the ​ (a)   system.

When the vessel is full, the muscles contract releasing the urine as waste in the ​ (b)   system.