Question

Normal life span of RBC is approximately

• A. 60 days
• B. 90 days
• C. 120 days
• D. 180 days

Hint:

The normal life span of RBCs is about 120 days.

Answer 1

The Correct Option is C

Concept:
Red blood cells are blood cells mainly responsible for carrying oxygen with the help of haemoglobin.

Step 1: Formation of RBCs.
RBCs are formed in the bone marrow by a process called erythropoiesis.

Step 2: Life span of RBCs.
The average life span of human red blood cells is approximately 120 days.

Step 3: Destruction of old RBCs.
After about 120 days, old RBCs are mainly destroyed in the spleen, liver, and bone marrow.

Step 4: Checking options.
60 days and 90 days are shorter than the normal RBC life span.
180 days is longer than the normal RBC life span.
Therefore, the correct answer is 120 days. \[ \boxed{120\ \text{days}} \]