Question

keplers laws of motion imply that comets with highly elliptical orbits will...
a spend most of their time at great distances from the sun.
b be confined to the plane of the ecliptic.
c travel with a uniform velocity.
d spend most of their time near the sun.

Explanation:

Kepler's laws (especially the second law, law of equal areas in equal times, and the first law about elliptical orbits) imply that for comets with highly elliptical orbits, they move faster when near the Sun (so spend less time there) and much slower when far from the Sun, thus spending most of their time at great distances from the Sun. Option B is about the ecliptic plane (not directly related to highly elliptical comet orbits' time distribution). Option C is wrong as comets don't have uniform velocity (they speed up near the Sun). Option D is wrong as they move fast near the Sun, so spend little time there.

Answer:

A. spend most of their time at great distances from the Sun