One possible reason that there are not any really large insects currently living on Earth is that
A)gas exchange across their moist skin surfaces cannot support the metabolic needs of a large body.
B)they do not have as many papulae as echinoderms.
C)their gills do not have as many lamellae as fish gills.
D)the bulk flow of air through their tracheal tubes would be more difficult the larger the body and longer the tracheal tubes.

Question

Quizplus · Accepted Answer

Insects rely on a tracheal system for gas exchange, which becomes less efficient as body size increases due to the limitations in the diffusion of gases over longer distances.

One Possible Reason That There Are Not Any Really Large