Learn how disease works — the mechanisms by which normal physiology breaks down. This is Human Biology's natural "part 2": for each major system you learn the core disease processes — inflammation and healing, cell injury and adaptation, immune dysfunction (allergy, autoimmunity), fluid and electrolyte imbalance, ischemia and infarction, hypertension and heart failure, diabetes, COPD and asthma, kidney injury, anemia, and the basics of how tumors form — always tracing a symptom back to its mechanism (why the swelling, why the pain, why the lab value moves). Each question teaches the underlying process and names the classic mix-ups (exudate vs transudate, type 1 vs type 2 diabetes, systolic vs diastolic heart failure). Built on standard pathophysiology teaching (Robbins-style) and the clinical sections of the free OpenStax corpus — great for nursing, allied-health, and pre-med review. Educational only — how disease processes work in general, NOT diagnosis, treatment, or medical advice; individual care belongs to a qualified professional.