Answer a:
Gaze backtracked on start of the second line, after reading the first two words "This theory".
Answer b:
Fixation was longer on "theory" of the second line of first paragraph.
"Ridiculed" and "species" were also fixated more as compared to other words.
Answer c:
Part(a): Regression in saccadic movements during silent reading generally happens when one tries to comprehend the meaning of the sentence as a whole. On reading "theory", the subject tried to understand the first line. And since, it is not a common theory for a science student it required one to go back to understand it. If it had been a theory like "force applied on a body equals acceleration times mass", most likely the subject would have comprehended it in one go itself.
Part(b): Fixation on a word in saccadic movements during silent reading generally happens when the word is not familiar(Williams & Morris, 2004) or frequent(Inhoff & Rayner, 1986). Being not a frequent speaker/reader in english, I am not used to finding "ridicule" in everyday communication/reading. So its an infrequent word, hence longer fixation. Similarily, "species" is not a very common word.
[1]Inhoff, A. W., & Rayner, K. (1986). Parafoveal word processing during eye fixations in reading: Effects of word frequency. Perception & Psychophysics, 40, 431-439
[2]Williams, R.S., & Morris, R.K. (2004). Eye movements, word familiarity, and vocabulary acquisition. European Journal of Cognitive Psychology, 16, 312-339.