IGCSE Biology 2026 Coordination and Response Practice Test – Comprehensive All-in-One Study Guide for Exam Success!

When the body gets warmer, sweat glands release fluid onto the skin. The important idea is evaporation: as sweat changes from liquid to vapor, it takes energy from the skin to power that change. That energy comes from the body, so heat is drawn away and the skin (and overall body) cools down. This evaporative cooling is why you feel cooler after sweating. How fast cooling happens depends on conditions: dry air and good airflow let sweat evaporate quickly, while humid air slows evaporation. So sweating helps regulate temperature by removing heat through evaporation, not by adding heat.