Submitted by admin on Mon, 04/28/2014 - 18:09
definition:
A fibrous substance consisting of polysaccharides, which is the major constituent in the exoskeleton of arthropods and the cell walls of fungi.
sentence:
There are a few other animal carbohydrates, notably chitin, the substance which constitutes the hard outer casing of insects and crustaceans.
difficulty:
hard
toefl frequency:
1
toefl classification: