The question is incomplete as it does not have the options-
a. superfluous organ
b. extra appendage
c. vestigial structure
d. living fossil
e. chromosomal aberration.
Answer:
The correct answer will be option-vestigial structure
Explanation:
Vestigial structure are the structures which do not play any role in the organisms but still are inherited from the ancestors to maintain the fitness of the organisms.
Vestigial organs are found in many organisms including humans in which the presence of vermiform appendix do not play any role but it used to play roles in the ancestors of humans as they carried the cellulose-degrading bacteria.
Thus, a vestigial structure is the correct answer.
The trachea has an epidermis layer that acts as a barrier and protects organs from things such as : dust, mucus and also pathogens Hope that helps :)
The answer would be population
