Omg, he was using sarcasm to point out the fact that the OP is an idiot for complaining about his mother saying that chickens aren't mammals, because they are in fact NOT mammals. They are birds. Therefore, saying that tomatoes are vegetables when they are really fruits, dolphins are fish when they are really mammals, and spiders are insects when they are really arachnids, is designed to point out obvious stupidity.

WTF? Well, just get a scientific textbook or something, if she won't believe Google / Wikipedia.

im not black :(

Tabernac, tomatoes are fruit.

Everyone knows that chickens are part of the big cat family

It was sarcasm dolphins aren't fish spiders aren't insects and tomatoes aren't vegetables

Understandable her confusion is. They are not mammals but in fact belong to the class aves. Then again, you already knew this. Instead of fighting about it, just make a bet, google it, and reap nothing. Because there is no way in he'll she'd pay up!

Your mum has a degree in chickens?!

Spiders are arachnids, and dolphins are aquatic mammals. They breathe their air through a blowhole, not gills.

That would mean that basically everything is a fruit. Except carrots, potatoes, etc. But then what about pineapples?! Or coconuts?!