Answer:
A field sparrow is an animal.
Explanation:
Collins and Quillian used this sentence because it was the simplest and easiest for the network to search, evaluate and rate for the system.
It is the easiest sentence because it has no repeated words, "A field sparrow is a bird" has no repeated word either, but "sparrow" and "bird" can be classified as the same, it's easier for the network to search "A field sparrow is an animal".
