- Blood is made up of blood cells
- Blood is a vehicle for carrying oxygen from the lungs to the rest of the body
- Hence, blood cells carry oxygen to the body

- Red blood cells contain hemoglobin
- Red blood cells are a kind of blood cell
- Hence, red blood cells are a kind of blood cell that contain hemoglobin

- Red blood cells are a kind of blood cell that contain hemoglobin
- Hemoglobin is a kind of protein that carries oxygen
- Hence, red blood cells are a kind of blood cell that contain a protein that carries oxygen

- Blood cells carry oxygen to the body
- Red blood cells are a kind of blood cell that contain a protein that carries oxygen
- Hence, red blood cells carry oxygen throughout the body

So, red blood cells carry oxygen throughout the body
Question: What carries oxygen throughout the body?
Context: - Red blood cells contain hemoglobin 
- Hemoglobin is a kind of protein that carries oxygen 
- Blood is made up of blood cells 
- Blood is a vehicle for carrying oxygen from the lungs to the rest of the body 
- Red blood cells are a kind of blood cell