Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski Onlain -

: By filtering vast amounts of water, bivalves like mussels and oysters act as natural water purifiers in ecosystems.

: The body is laterally compressed and enclosed in a bilateral shell. This shell consists of three layers: an outer organic layer (periostracum), a middle calcareous layer, and an inner pearly layer (nacre). : By filtering vast amounts of water, bivalves

: The nervous system is simplified, consisting of three pairs of ganglia. Ecological and Economic Importance : The nervous system is simplified, consisting of

: They possess an open circulatory system with a heart and vessels. : Many species, such as scallops and oysters,

: Students typically study the Anodonta (swan mussel), Unio (painter's mussel), and marine species like the edible mussel and giant clam.

: Many species, such as scallops and oysters, are significant food sources for humans. Freshwater pearl mussels are also cultivated for pearl production.