The answer is D. The other answers are improper. D is the only answer that makes sense.
Answer: This picture was taken from the top of Lookout Mountain.
Abba abba but I could be wrong
Answer:
The word "protracted" means lasting longer than expected, or unusually long, so what protracted most clearly means based on the context of the excerpt is how the time period of celestial motion studies must have lasted unusually long.
