1) you want to increase friction when it gets cold. If you're outside and it's really cold, you're going to rub your hands to warm them up, therefore friction is increasing
I'm not do sure about decreasing.
Answer:
Respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce use able cellular energy. This energy is used to fuel growth and all of the normal cellular functions.
Short Answer
They combine to produce cellular energy.