Task: Categorize the tweet's emotional expression, classifying 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 reflect the tweeter's state of mind.
Tweet: Africa has unique and tremendous problems with war, overpopulation, starvation and tribalism which makes moving Africa forward hard.
This tweet contains emotions: 
disgust, sadness