Q.Which one of the following types of cells lack nucleus in humans?

In most mammals, mature erythrocytes (red blood cells) have no nucleus, unlike the other cell types listed, all of which are white blood cells and are n …

Red blood cells, or RBCs (erythrocytes), have an unusual structure well suited to their role: in most mammals, including humans, mature RBCs have no nucleus, and they are biconcave in shape, packed with haemoglobin for carrying respiratory gases. …

Method: Comparing a Structural Feature Across Related Cell Types

Use this approach whenever an MCQ's options mix one cell type from a different category with several from the same category.

Steps

Step 1: Group the options by broader category first

Here, one option (erythrocyte) is a red blood cell, while the other three (neutrophil, eosinophil, monocyte) are all white blood cells — noticing this grouping often reveals the answer lies BETWEEN categories, not within one.

Step 2: Recall the single defining structural feature that separates the categories

Mature erythrocytes are anucleate in mammals; every white blood cell type is nucleated, without exception.

Step 3: Confirm none of the specific options named is an exception to the general category rule …