Which of the following respiratory surfaces lack physical protection from the external environment?
a. internal gills
b. lungs
c. tracheal system tubes
d. external gills
Ans: d. external gills
Biology & Microbiology
You might also like to view...
At rest, a nerve cell has a high concentration of ____ inside and a high concentration of ____ outside
a. acetylcholine; chlorine b. sodium; potassium c. potassium; sodium d. calcium; phosphorus e. phosphorus; calcium
Biology & Microbiology
Which structure is a rod of stiffened support
tissue? a. A b. B c. C d. A and B e. none of these
Biology & Microbiology
Each cell is able to maintain an internal state of chemical and physical stability. This is called
a. metabolism. b. homeostasis. c. physiology. d. adaptation. e. evolution.
Biology & Microbiology
Which molecule is believed to have preceded the other two during the evolution of life?
A. DNA B. RNA C. Proteins
Biology & Microbiology