Submitted by admin on Fri, 05/02/2014 - 22:48
definition:
A thickened and hardened part of the skin or soft tissue, especially in an area that has been subjected to friction
sentence:
According to them, the genome of the ostrich has the ability to let the skin form calluses when the skin is abraded.
difficulty:
hard
toefl frequency:
1
toefl classification: