Onlain - Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski

For further study and visual aids, students can refer to educational platforms like Yaklass or watch lesson summaries on YouTube .

: They possess an open circulatory system with a heart and vessels. For further study and visual aids, students can

: 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,

: Many species, such as scallops and oysters, are significant food sources for humans. Freshwater pearl mussels are also cultivated for pearl production. : By filtering vast amounts of water, bivalves

: They breathe through plate-like gills (ctenidia) located in the mantle cavity.

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

: Unlike gastropods (snails), bivalves lack a distinct head. Their body consists of a torso and a muscular "foot" used for burrowing or anchoring.