Which parts of a clam are likely to be preserved

The hard parts are preserved.

Explanation:

Clam is the common name given to several species of bivalve molluscs of the order Veneroida, namely those belonging to the Lucinidae, Cardiidae and Veneridae families. Many are used in human food, in addition, the hard parts are preserved and used later.

The clam has thirty percent more protein than the mussel, another very popular seafood worldwide.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.