Write the letter of the term or phrase that best matches the numbered description. 1. produces electrical energy chemically 2. energy sources that are still in development 3. includes lifestyle changes 4. produces electrical energy using the temperature difference between two layers of water a. alternative energy b. fuel cell c. energy efficiency d. energy conservation e. ocean thermal energy conversion (OTEC) 5. percentage of energy that does useful work

Which of the following statements best characterizes changes to agriculture in the united states since 1900? a. increased mechanization has reduced the need for labor. b. increased mechanization has increased the need for water, thereby increasing the need for labor. increased mechanization has increased the use of land, thereby increasing the need for labor. d. increased mechanization has increased food production, thereby increasing the need for labor. select the best answer from the choices provided.

What man-made lake was created by the building of the hoover dam?

Which state in the united states founded the first true public zoo?