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.
The hemoglobin in red blood cells combines with oxygen in the lungs, transporting that oxygen to the tissues throughout the body. It also carries carbon dioxide from the tissues back to the lungs, where some of the carbon dioxide is exhaled.