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

The Class Bivalvia (Двустворчатые моллюски) is a group of aquatic mollusks characterized by a shell composed of two hinged parts. In the 7th-grade biology curriculum by S.V. Sumatokhin and V.V. Pasechnik, these organisms are studied for their unique evolutionary adaptations to a sedentary lifestyle. Key Biological Features

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

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

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

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

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

Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski Onlain [2K · 480p]

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

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

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

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

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

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