Forced Connection: Immune System × Spam Filter

Domain A: the body's immune system (detect invader → first-line defense → remember the invader → respond faster next time) Domain B: an email spam filter (receive → check patterns → update blocklist → block more accurately)

Find 3 'structural commonalities' the two domains share, and explain each in 2–3 sentences. Surface similarities like 'both block bad things' don't count. Write while specifying which element of A maps to which element of B. Hint: thinking through malfunction cases (mistaking friend for foe) broadens the layers.