Pick from:
A). Lungs;
B). Mass;
C). oxygen;
D). eardrum;
E). gills;
F). ovaries;
G). Organs;
H). Bodies;
Q: Fact 1: Echinoderms lack respiratory and excretory systems. Fact 2: Lung mechanics and gas exchange are topics during study of the respiratory system. Given the two facts above, what do Echinoderms lack?
A:
A).