A change in the color of a substance -- this one is indeed a chemical change. Think of iron, if iron turns reddish, it's a completely different substance.
Answer:
How does cellular respiration work in animals?
When an animal breathes, it takes in oxygen gas and releases carbon dioxide gas into the atmosphere. This carbon dioxide is a waste product produced by the animal's cells during cellular respiration. Cellular respiration occurs in the individual cells. Digested foods have chemical energy stored in them.
Explanation:
Turn off the lights when not in use, turn off all appliances when not used, remove your phone from the charger when its at full charge, heaters and air conditioners should be turned off when not in use, and using a regular sharpener rather than an electric one. Hope this helps. :)