These animals are all invertebrates
Acids are donors of protons (H+) and bases are acceptors of protons.
For example:
1) hydrochloric acid (HCl) in reaction with water give one proton to water and become chloride anion (Cl-).
2) ammonia (NH3) Is base, in reaction with water accepts one protone and become ammonium cation (NH4+).
I would say all if no statements are available
The mass of the water is 1.20 - 0.80 = 0.40 grams.
The % of water is (0.40 / 1.20 ) * 100 = 33 1/3%