▶️ Answer/Explanation
(a) Matching Functions:
• antibody production \(\rightarrow\) white blood cells
• transport of oxygen \(\rightarrow\) red blood cells
• transport of oestrogen \(\rightarrow\) plasma
• phagocytosis \(\rightarrow\) white blood cells
(b) (i) High Iron Foods:
The two correct boxes are:
• green leafy vegetables (\(\checkmark\))
• red meat (\(\checkmark\))
(b) (ii) Roles of Blood Clotting:
1. To prevent blood loss (stop bleeding).
2. To prevent the entry of pathogens (such as bacteria and viruses) into the body.
(c) Main Vessel:
The aorta.
Expert Explanation:
Blood Composition:
• Red blood cells: Contain haemoglobin to bind and transport oxygen from the lungs to respiring tissues.
• White blood cells: Part of the immune system. Phagocytes engulf pathogens (phagocytosis), and lymphocytes produce antibodies to neutralize them.
• Plasma: The liquid component that transports dissolved substances, including hormones (like oestrogen), nutrients (glucose, amino acids), carbon dioxide, and urea.
Clotting: When platelets encounter a damaged vessel, they trigger the conversion of fibrinogen to fibrin. This forms a mesh that traps blood cells, creating a clot to seal the wound and block infection.
Circulation: The aorta is the largest artery, carrying high-pressure, oxygenated blood from the left ventricle to the systemic circulation (the rest of the body).