Gdz — Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski

(class Bivalvia ) are a unique group of aquatic mollusks characterized by a shell consisting of two hinged valves and, most notably, the absence of a head . In the Grade 7 Biology curriculum by Sumatohin, they are studied as essential bio-filters and members of aquatic ecosystems. Key Biological Features

: As filter feeders, they clean bodies of water by removing organic suspension. gdz biologiia 7 sumatokhin klass dvukhstvorchatye molliuski

: Consists of two symmetrical valves connected by a flexible ligament and a "lock" (hinge). (class Bivalvia ) are a unique group of

: Some species (pearl oysters) produce pearls and mother-of-pearl (nacre) used in jewelry. : Consists of two symmetrical valves connected by

: Like most mollusks, they have an open circulatory system where the heart pumps blood into the body cavity. Internal Anatomy Summary Characteristic Digestive

: The body is laterally compressed and divided into two main parts: the trunk and the wedge-shaped foot . Unlike gastropods, bivalves lack a head, tentacles, and eyes.