Some new appliances, like refrigerators, stoves, dishwashers, and air conditioners may have the Energy Star label if they meet certain high-efficiency standards. Think about the electrical appliances you use in your home. Remember that video game consoles, computers, televisions, and DVD players all use electricity, too. What are some ways that you could reduce the amount of electricity that you and your family use? Explain how you could change some of your energy-use habits and the benefits those changes might have on climate change.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

i'm pretty sure its b i might be wrong though!

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.

4d^55s^1 ( third choice)