Man & Dog In A Bar

One day a man walked into a bar with his dog. He walked up to the counter and the bartender said”We don’t allow dogs in this bar.”The man replied”But sir,my dog is a smart dog it can talk!”The bartender didn’t look impressed but gave him a shot anyway.The man then asked his dog”What grows on a tree?”The dog replied”Bark, Bark”The man again asked his dog and said”What’s above a house?”The dog said “Roof, Roof”Then for the final time the man asked his dog “What’s the opposite of smooth?” The dog replied “Rough, Rough”Very unimpressed the bartender threw them both out of the bar.The dog then turned to his owner and said”Which one did I get wrong?”