Zheng he's naval voyages into the indian ocean served to
1. create a large-scale trading post empire throughout the middle east and east africa
2. enhance the prestige of the chinese navy during the early ming dynasty
3. highlight the role played by ethnic manchus during the qing dynasty
4. establish long-term chinese dominance of indian ocean trade

Which of the following activities would conserve the most energy? installing a dimmer switch on a light using a blender instead of a food processor hanging clothes to dry on a clothesline instead of ironing them opening a window instead of turning on the air conditioning setting your computer's screen saver to turn on after less time has elapsed