The sieve plate, stone canal, circular canal, and radial canals of a sea star are structures of the
a. nervous system.
b. water-vascular system.
c. digestive system.
d. excretory system.
d
You might also like to view...
All lipids are ________.
A. hydrolytic B. water-loving molecules C. hydrophilic D. hydrophobic
Four of the following are modern apes. Which is not a modern ape?
a. gibbon b. new world monkey c. chimpanzee d. gorilla e. orangutan
With which of the following statements would a biologist be most inclined to agree?
A) Humans and other apes represent divergent lines of evolution from a common ancestor. B) Humans represent the pinnacle of evolution and have escaped from being affected by natural selection. C) Humans evolved from chimpanzees. D) Humans and other apes are the result of disruptive selection in a species of chimpanzee.
Which of the following is/are true about enzymes?
A. Enzymes are highly specific for the substrates they react with and catalyze only one or a limited set of possible reactions with those substrates. B. Enzymes are catalysts that speed up reactions. C. Enzymes are proteins that can be denatured by changes in pH or temperature. D. All of the choices are correct.