Task: Evaluate the tweet for emotional cues and classify it as either 'neutral or no emotion' or as one or more of the specified emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that indicate the tweeter's state of mind.
Tweet: Did you know apples turn brown when a enzyme called polyphenol oxidase reacts with oxygen! Well I do #dull #applefacts 🤓🍏
This tweet contains emotions: 
joy, optimism