Question

Which of the following traits exist in mollusks? I. 3-chambered heart II. gills III. 1-way digestion IV. spinal cord

a. I, II, IV
c. I, III, IV
b. I, II, III
d. I, II, III, IV

Answer 1

B. I, II, III

Mollusks have 3-chambered heat. They have gills and they have 1-way digestion.

Other characteristics of mollusks are:
1) Bilaterally symmetrical
2) Body has more than two cell layers, tissues and organs
3) body without cavity
4) body monomeric and highly variable in form, may possess a dorsal or lateral shells of protein and calcarous spicules.
5) has a nervous system with a circum-oesophagal ring, ganglia and paired nerve chords
6) has an open circulatory system with heart and aorta
7) has a pair of kidneys
8) reproduction normally sexual and gonochoristic
9) feed a wide range of material
10) live in most environment