Hydropower
a. uses the energy of moving water
b. is a nonrenewable energy source
c. releases toxins, like nitrogen oxide
d. depends on time of day and time of year

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

heat the gas and measure the pressure

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.