Fact 1: Humans have collected and grown mushrooms for food for thousands of years. Fact 2: Yeast and mushrooms are types of fungus. Given the two facts above, what living thing has collected and grown fungus as a source of food for thousands of years?

Possible answers:
[a]. humans;
[b]. grocery stores;
[c]. honeybees;
[d]. animals;
[e]. pigs;
[f]. fungi;
[g]. trees;
[h]. plants;
Answer:
[a].