A generator is a machine which makes:

electricity
magnetism
magnetic materials

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.

Each line (unit) on the horizontal axis represents: 5 years 10 years 20 years all of the above

Which of the following could represent a single-replacement reaction? a. element + compound = element + compound b. element + element = compound c. compound +compound = compound + compound d. compound = element + element