Electrons are modeled using a "cloud" around the nucleus because they
a) can not be precisely located.
b) travel at the speed of light.
c) exist in many places at once.
d) move in an orbit about the nucleus.

During the apollo moon missions, astronauts were concerned about the effects of newton's third law of motion when: o a. they ejected waste water, because they were concerned that it would push them off course. o b. they reentered earth's atmosphere, because they were carrying heavy moon rocks. o c. they took off from earth, because a large force was required to generate large acceleration. o d. they detected incoming space debris, because the inertia of the debris could damage their ship.