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

: Species like oysters, mussels, and scallops are important food sources for humans and marine life. gdz biologiia 7 sumatokhin klass dvukhstvorchatye molliuski

: As filter feeders, they clean bodies of water by removing organic suspension. Mouth (near the foot), stomach, liver, and intestine

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

: Consists of two symmetrical valves connected by a flexible ligament and a "lock" (hinge).

(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