4.A high-quality sleeping bag will keep you warm even during a winter camping trip high in the mountains. How do you stay warm when the air around you is very cold? A. The sleeping bag produces thermal energy that keeps you warm.
B. The sleeping bag transfers thermal energy from the air to your body.
C. The sleeping bag slows the transfer of thermal energy produced by your body into the air.
D. The sleeping bag increases the production of thermal energy by your body

I think it's C

Explanation:

Can I have brainliest? It would help me out, if not thanks anyways! Hope this helped and have a nice day!

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.