IGCSE Biology – Coordination And Response Practice Test

Homeostasis is about keeping the body's internal conditions steady even as the outside environment changes. For temperature, the body tries to stay around 37°C. When it gets too hot, cooling mechanisms kick in—sweating and vasodilation (blood vessels near the skin widen) to lose heat. When it’s too cold, warming responses occur—shivering and vasoconstriction (blood vessels narrow) to conserve heat. This regulation relies on negative feedback, where a deviation from the set point triggers responses that push the value back toward normal. The other ideas don’t fit because homeostasis isn’t about a constant rise in temperature, nor is it just a temporary change. It’s about maintaining a stable internal state, and it involves responses to both internal and external changes, not only external stimuli.