Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski | HD |

(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

: Swan mussels ( Anodonta ), thick-shelled river mussels ( Unio ), and giant clams ( Tridacna ). gdz biologiia 7 sumatokhin klass dvukhstvorchatye molliuski

Mouth (near the foot), stomach, liver, and intestine. They lack a radula (grating tongue). Plate-like gills (ctenidia) located in the mantle cavity. Excretory Two kidneys that open into the mantle cavity. Nervous Simplified, consisting of three pairs of ganglia. Ecological and Economic Importance (class Bivalvia ) are a unique group of

: 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. Mouth (near the foot), stomach, liver, and intestine