Classifying Immunity as Active/Passive and Natural/Artificial

Steps:

• Immunity types: active (body produces antibodies) vs. passive (antibodies received from external source).
• Subtypes: natural (via infection or maternal transfer) vs. artificial (via vaccine or injection).
• Label 1 shows antibody transfer without body production, indicating passive immunity.
• Labels 2 and 3 differentiate maternal transfer (natural) from injected antibodies (artificial).

Why D is correct:

• D matches passive for 1 (external antibodies), natural for 2 (maternal, e.g., breast milk), and artificial for 3 (medical injection, per immunology definitions).

Why the others are wrong:

• A: Incorrectly labels 1 as active (body must produce antibodies) and 3 as natural (3 involves intervention).
• B: Labels 1 as active, but 1 depicts passive transfer.
• C: Swaps 2 and 3, making 2 artificial (but 2 is natural maternal) and 3 natural (but 3 is injected).

Final answer: D