Fair. Both are sufficiently ancient, but cellulose bearing species diverged earlier chitin bearing ones. Exact timing on it tho is nebulous. So either will do.
I only mention cellulose specifically because it is the historic precursor to the first man made plastic, celluloid. But there are now processes to convert chitin to chitosan, which is a moldable plastic.
Shit I’d argue chitons the first plastic.
Fair. Both are sufficiently ancient, but cellulose bearing species diverged earlier chitin bearing ones. Exact timing on it tho is nebulous. So either will do.
I only mention cellulose specifically because it is the historic precursor to the first man made plastic, celluloid. But there are now processes to convert chitin to chitosan, which is a moldable plastic.