Final answer:
Considering Newton's Law of Universal Gravitation, if the distance between two planets decreases by a factor of 3, the gravitational force between them will increase by a factor of 9.
Step-by-step explanation:
The subject of your question falls under the realm of Physics, more precisely, the laws of gravitation. According to Newton's Law of Universal Gravitation, the force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Therefore, if the distance between the two planets decreases by a factor of 3, the gravitational force will increase by a factor of 9 (since 32 = 9). So, the correct answer to your question is D) It will increase by a factor of 9.
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