Task: Determine the prevailing emotional tone of the tweet, categorizing it as either 'neutral or no emotion' or as one or more of the given emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that most accurately represent the tweeter's mental state.
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