:which of the following is true about comets in our solar system? a. being mini-stars, they are made of gas. b. they were discovered in the 17th century. c. they take roughly the same amount of time to orbit the sun. d. they all orbit the sun due to the sun’s gravity.

I think the answer is D. I'm sorry if it is incorrect.

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.