Question

(a) What is blood? Why is it red?
(b) State the functions of blood in our body.
(c) Name a circulatory fluid in the human body other than blood.

Answer 1

(a) Blood is a red colour connective tissue that circulates in our body. Blood has an extra-cellular matrix called plasma, where red blood cells, white blood cells and platelets float. Blood is red because of the presence of haemoglobin. Haemoglobin is a red colour pigment, found in red blood cells.

(b) Following are the functions of blood:

• It transports oxygen from the lungs to the cells.
• It carries carbon dioxide, a waste product, from the body cells to the lungs.
• It fights diseases and infections.
• It regulates the body temperature.
• It carries hormones to different organs of the body.

(c) Other than blood, lymph is a circulatory fluid in human body.