Your functions and blood are all moving by the force of gravity, so when everything is raised or lowered(moving your arm), your pulse wave changes. This can also result from subtlty in higher blood pressure, when activity occures. Just as your pulse waves changes in the rest of your body when excersising, you will have a slight change in pulse when simply moved your arm up and down, you're gettin' that blood pumping! ;)
Hope this helps :)
Answer:
Many people don't understand why or how other people become addicted to drugs. They may mistakenly think that those who use drugs lack moral principles or willpower and that they could stop their drug use simply by choosing to. In reality, drug addiction is a complex disease, and quitting usually takes more than good intentions or a strong will. Drugs change the brain in ways that make quitting hard, even for those who want to. Fortunately, researchers know more than ever about how drugs affect the brain and have found treatments that can help people recover from drug addiction and lead productive lives.
Media is less effective then peers because of one thing, Peer Pressure.
Peer pressure is when your friends are saying " you have to try this because all the cool kids do it." Also the media at home on the television isn't effective because you have your parents there and they say its bad.
