OPT:
(i) insects;
(ii) bees;
(iii) a fish;
(iv) barnacles;
(v) animals;
(vi) carbon;
(vii) feces;
(viii) humans;

Fact 1: Some arthropods have special excretory structures. Fact 2: All insects are arthropods. Given the two facts above, what sometimes has special excretory structures?
Answer:
(i)