In my opinion, i think the first one is the best one since we're cutting down on paper wasted in mails when its better to do it online.
"paying bills online instead of sending paper through mail"
Well simple the warm water then replaces the cold current that sinks to the ocean floor.
Solar energy is a good alternative to replace fossil fuel as the major energy source because solar power is renewable at absolutely no cost to supply energy infinitely.
Gravity!! It also keeps the planets in orbit!
