Directions: Select ALL the correct answers.

Friction is a force that can oppose the motion of two objects that are touching each other. Which of the following are examples of friction?

A. A nail holds two wooden boards together.
B. A parachute softens the landing of a skydiver.
C. A space probe orbits the Moon.
D. The brakes on a bike rub against the wheel.

true

explanation:

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.