The components of blood in man are?

1. Analyze the question The question asks for the components (parts) of human blood. You need the option that lists all the main components.

2. Explain the concept Blood is a fluid connective tissue made of two main parts:

• Plasma (the liquid part, about 55%): a straw-coloured fluid that is about 90% water. It carries dissolved food, hormones, salts, carbon dioxide and waste products such as urea.
• Blood cells and cell fragments (the solid part, about 45%): • Red blood cells (erythrocytes) carry oxygen using haemoglobin. • White blood cells (leucocytes) fight infection and produce antibodies. • Platelets (thrombocytes) help blood clot at wounds.

3. Solution, option by option

• A: Lists "plasma and water" separately. Water is already part of plasma, not a separate component, and platelets are missing. Wrong.
• B: Leaves out platelets. Incomplete.
• C: Leaves out plasma, which is the largest component. Incomplete.
• D: Red blood cells, white blood cells, plasma and platelets. This covers all four standard components of blood.

4. Answer The correct option is D.

5. Tip Remember blood as "P-R-W-P": Plasma, Red cells, White cells, Platelets. If an option leaves out any one of these four, it is incomplete. Also watch out for options that list water separately, because water is part of plasma.