system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Is there a canon explanation for why so many aliens are humanoid?
gpt
For most, such as Sullustans and Abednedo, convergent evolution. Species in the galaxy that evolve into intelligent toolmakers tend to have the same basic body shape. 

The species that have human shaped heads with colorful skin or other small differentiators (like Twi'leks and Mirialans) are "near-humans" who have human ancestry but adapted to life on other planets or interbred with aliens.