Use words to express. any number that begins a sentence, title, or text heading. Whenever possible, reword the sentence to avoid beginning with a number. Examples: 1  Ten participants answered the questionnaire.  Forty-eight percent of the sample showed an increase; 2% showed no change.
Transport of oxygen in the blood Blood Blood is an 'aqueous body fluid'. In other words it is water containing a whole range of substances. It is contained in a complex network called the vascular system and is pumped around the body by the heart.
Red blood cells at work. Hemoglobin is the protein inside red blood cells that carries oxygen. Red blood cells also remove carbon dioxide from your body, transporting it to the lungs for you to exhale.