C. To live in a group with other organisms
Involuntary, meaning things in the body such as your heart is all regulated to act unconsciously while also receiving directives from the brain.
Provision of energy. Fats are a source of energy in the human diet, together with carbohydrates and proteins, the other two main macronutrients.
Answer:
The acidity level of water is measured by the pH scale. Pure water has a pH of 7, which is neutral. However, natural rainwater actually has a pH of 5.6 because it gets exposed to the gases in the atmosphere, making it a bit acidic. True acid rain will have a pH level measuring from 5.0-5.5.
