system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Crumpets. How does dough get so holey?
gpt
Carbon dioxide bubbles form in the glutinous structures due to yeast's metabolization of sugars in the dough.

It is the same reason bread rises, except that crumpets have different ratios of ingredients than bread and are intended to have a particularly spongy texture.