<span>Nonliving things also have unlimited duration of existence. While living things die and decompose, nonliving things such as rocks, mountains, air and water have existed for millions of years. They may grow, but they do so only by accretion, which is the process of growth by accumulating added layers of matter.</span>
The three phases of matter differ in properties just because of the proximity of their molecules. The solid phase is the most organized of all. Its atoms are compactly arranged together and has the strongest intermolecular forces to keep them together. This is why they have a definite shape and volume. The liquid phase have molecules that are far away from each other, but not as far as that of the gas phase. The liquid and gas phases can be lumped into one group called fluids because they have the same property - they take the shape and volume of their container.
To make an analogy, see the attached picture for your reference.
An organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other's expense.
Answer
D. The acceleration vector of the planet points towards the center of the circle.
Explanation
For planetary motion , the velocity vector is always in a direction that is tangential to the direction of motion, not towards the center. Even though the speed of the planet may stay constant, it's velocity changes because it is constantly changing it's direction.
The centripetal force, which in this case is the force of gravity always points in the direction of the the center. The acceleration vector always points in the direction of the of the center of the circle just like the centripetal force.
