Which of the following is considered an energy source and a building block for the human body? a)fats b)water c)proteins d)carbohydrates

In which way does nicotine cause addiction? by stimulating the brain's pleasure center by increasing blood-sugar levels by decreasing dopamine levels by reducing depression and anxiety

Which form of birth control good people use without altering hormonal systems are blocking sperm from fertilizing an egg

Answer in a couple of paragraphs, 1 or 2 at the most if anything! 20 points + brainliest--> explain what all the systems in your body do to work together < --list of systems needed: circulatory systemrespiratory systemdigestive systemexcretory systemnervous system