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.
Each type of blood cell has a specific job. 1  Red blood cells carry oxygen from the lungs to the rest of the body. 2  Platelets form blood clots in damaged vessels to stop bleeding. 3  White blood cells help prevent and fight infection by destroying bacteria, viruses and other foreign cells or substances.