What are the different types of keys in music and how do they affect the overall sound of a musical composition?

In music, there are different types of keys such as major and minor keys. Keys affect the overall sound of a musical composition by determining the notes that are used and the emotional feel of the music. Major keys often sound bright and happy, while minor keys can sound more somber or melancholic. The key of a piece can influence the mood and atmosphere of the music, creating different emotional responses in the listener.