Option 1: Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.

This option is incorrect. Haemoglobin in red blood cells can bind to both oxygen and carbon dioxide.

Option 2: Haemoglobin of RBC can carry both oxygen and carbon dioxide.

This option is correct. Haemoglobin in red blood cells has the ability to bind to both oxygen and carbon dioxide. In the lungs, haemoglobin binds with oxygen to form oxyhemoglobin, which is then transported to tissues throughout the body. In the tissues, haemoglobin releases oxygen and binds with carbon dioxide, forming carbaminohemoglobin. This carbaminohemoglobin is then carried back to the lungs to be exhaled.

Option 3: Haemoglobin of RBC can carry only carbon dioxide.

This option is incorrect. While haemoglobin does bind with carbon dioxide, it also carries oxygen.

Option 4: Haemoglobin is only used for blood clotting and not for carrying gases.

This option is incorrect. Haemoglobin is primarily responsible for carrying oxygen in the blood and assisting with the transportation of carbon dioxide. It is not involved in blood clotting, which is primarily mediated by other proteins called clotting factors.

In conclusion,