"A pawpaw is a fruit" just sounds awkward.
My answer, "A pawpaw is fruit" should not be marked wrong.
"Pawpaw is (a) fruit" should also be accepted.
Nicknames for "pawpaw": "custard apple," "poor man's banana" & "Indiana banana.".
Maybe "A pawpaw is a fruit" is better. "Pawpaw is fruit" seems to fit quite well here. "Pawpaw is a fruit" seems neither one nor the other. I'd give "correct" for any of these just so that we could get on quickly to the next exercise!
There is no such thing as pawpaw. It is papaya
I prefer the word "papaya" too, but "pawpaw" is in the dictionary as another term for papaya:
Dear course contributors, please stop correcting articles.
The course developers don't necessarily read these comments.
You have to use the report flag to request a correction ("My answer should have been accepted.")