The rapid growth of the human population is a concern because a. natural resources are abundant b. the carbon hectare is increasing c. if we continue to grow, the population will exceed earths biocapacity d. as a population increases, so does its per capita ecological footprint e. all of the above

More than 150 years ago, inventors began working on a bright idea that would have a dramatic impact on how we use energy in our homes and offices. This invention changed the way we design buildings, increased the length of the average workday and jumpstarted new businesses. It also led to new energy breakthroughs -- from power plants and electric transmission lines to home appliances and electric motors.

Like all great inventions, the light bulb can’t be credited to one inventor. It was a series of small improvements on the ideas of previous inventors that have led to the light bulbs we use in our homes today.