Solution:
All except India are islands, while India is a peninsula.

Solution:
All except Disco are folk dances.

Solution:
All except Moraines are structures formed by the sea, while moraines are formed by glaciers.

Solution:
In all other groups, there is a gap of two letters between first and second as well as between second and third letters.

Solution:
All except Lizard are insects, while lizard is a reptile.

Solution:
All except Flute are string instruments.

Solution:
All except Grass are non-flowering plants.