Ambiguous pronouns former and latter

I have two questions about the following two sentences:

(1) "One explanation should be accepted over another if it can explain the evidence better."

(2) "One explanation should be accepted over another if it can explain the evidence better than the other."

Question 1: Is "it" an ambiguous pronoun in either sentence?

Question 2: Does replacing "it" with "former" in sentence 1 make that sentence better?

Thanks for your opinions.