An engineer is investigating ways to improve gas mileage. his initial hypothesis is, "if we use higher octane gasoline, then the gas mileage will increase." what should his control group be? a) the type of car used in the testb) using higher octane gasolinec) the gas mileage of the test vehiclesd) some cars using regular octane gasoline

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Use 4 to 5 complete sentences, explain the concepts of beats and how beats are produces.

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)