What is the passage mainly about?

How repeated muscle motion makes heat when the body gets cold (The passage follows a drop in temperature to brain signals, muscle motion, and heat.)

A “thermostat” is something that

watches temperature and responds when it changes (The brain’s control center is compared with a room thermostat that responds to temperature.)

What do the brain’s signals make muscles do?

Tighten and release many times (The second paragraph says the muscles tighten and release repeatedly.)

Why can shivering make a person tired?

Repeated muscle motion uses energy (The final paragraph connects the energy used by muscle motion with tiredness.)

Why We Shiver: Level 1 Reading Comprehension Questions

Your body keeps its core temperature within a narrow range. It is often near 37 degrees Celsius, but the exact number changes with the person, time of day, activity, and place of measurement. When cold air pulls heat from your body, your temperature can begin to fall.

The brain watches for that change. A control center acts a little like a thermostat in a room. It sends signals that tighten and release your muscles many times. The quick, repeated motion is a shiver.

Moving muscles produce heat. A runner warms up for the same reason. Shivering uses muscle motion without waiting for you to choose it. The heat helps defend your core temperature.

Shivering also uses energy, so it can be tiring. It is one response to cold, not a promise that the body can handle any temperature. Strong or lasting shivering can be a sign to get warm and seek help when needed.

Comprehension questions