Which of the following statements is true? (a)the total amount of water in an ecosystem is always increasing. (b)thermal pollution is the main disadvantage of hydroelectric power. (c)wood and water are nonrenewable natural resources. (d)the greenhouse effect is primarily caused by cars and trucks.

Orion the hunter is known for two navigational stars. which pair of stars are they?

Which statements about wells are true? check all that apply. a) wells bring groundwater from the unsaturated zone to the surface of the water. b) wells need to be drilled below the water table. c) if water is pumped from a well too quicky, the well may run dry. d) water from wells is generally not safe to drink. e) water gushes from artesian wells due to pressure.

Which barrier to economic development is shown in the following examples?