15. satellites remain in orbit around earth because
a. the moon's gravitational pull on them is equal
to earth's pull.
b. no forces act on them.
c. their motors keep them moving in circles.
d. the curve of their paths as they fall matches
the curve of earth.

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

Which blood cell spend most of their time in the lymphatic system?

In 2015, about ten percent of total u. s. energy consumption was from renewable energy sources. renewable energy plays an important role in reducing greenhouse gas emissions. when renewable energy sources are used, the demand for fossil fuels is reduced. sanjay and his family want to cut back on their use of non-renewable resources at home. they are thinking of an alternate way to heat their home without adding more greenhouse gases or pollutants to the environment. which renewable resource would not fit into their plan? a) solar power b) burning wood c) constructing a wind turbine eliminate d) generating hydroelectric power