Available choices: [i] ice; [ii] rocks; [iii] amphibians; [iv] humans; [v] dolphins; [vi] snail; [vii] the sun; [viii] healing;
Given those answer options, answer the question: Fact 1: Healing requires rest. Fact 2: Sleep also allows the joints to rest. Given the two facts above, what requires sleep?
A:
[viii]