Identify 2 unique adaptations made by all animals in the phylum mollusca, the function of each adaptation, and your theory as to what pressures may have forced each adaptation and identify 2 unique adaptations made by all animals in the class bivalvia, the function of each adaptation, and your theory as to what pressures may have forced each adaptation.

and you!

2 unique adaptations made by all animals in the Phylum Mollusca are:
1) the Radula - it is a tongue-like plate that is used for diverse feeding methods. 
2) a well developed, muscular foot - used for clinging to surfaces, burrowing, anchoring in sediment, locomotion, swimming, modified into prehensile tentacles in octopus.

 2 unique adaptations made by all animals in Class Bivalvia
1) ctenidia - term used to identify its  gills which were  adapted for filter feeding
2) siphon - a modification of mantle tissue found inside the shell. It flushes water through the mantle and aids in the respiration, circulation, and waste removal of the organism.