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

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

Bi believe is the answer

An ecosystem is in a certain area and includes living and non living plus there is weather conditions and a biome is a large amount of area with similar climate.so ecosystem is based on weather and biome is based on the average climate