The conversation between human and AI assistant.
[|Human|] Given a list of words and descriptions, categorize the words into two distinct groups.
[|AI|] Group 1: Celestial Objects
- Pluto — dwarf planet
- Uranus — planet

Group 2: Chemical Elements
- Helium — chemical element
- Titanium — chemical element
[|Human|] 
Given a list of words and descriptions, categorize the words into two distinct groups.