Final answer:
In 'LUNAR,' the 'R' stands for 'retrograde rotation,' referring to the uncommon direction of celestial body rotation opposite to the norm in our solar system (Option E).
Step-by-step explanation:
The "R" in "LUNAR" stands for retrograde rotation, which is a term used in astronomy to describe the motion of an object that rotates or revolves in the direction opposite to most objects in the solar system.
This is particularly interesting as most celestial bodies, including planets and moons, typically rotate and revolve in the same direction due to the way the solar system formed from a rotating disk of gas and dust.
Retrograde rotation is often discussed in the context of planets like Venus and Uranus, which have such rotational characteristics.
Hence, the correct answer is Option E.
The complete question is: What does the "R" stand for in "LUNAR"? A. resources needed B. region (location) C. rescue required D. roll call E. retrograde rotation.