In paragraph 2, why does the author mention that the period for different horseshoe crabs ranges from 22.2 to 25.5 hours? A. To illustrate that an animal's internal clock seldom has a 24-hour cycle B. To argue that different horseshoe crabs will shift from daytime to nighttime vision at different times C. To illustrate the approximate range of the circadian rhythm of all animals D. To support the idea that external cues are the only factors affecting an animal's periodic behavior