: They breathe through plate-like gills (ctenidia) located in the mantle cavity.
For further study and visual aids, students can refer to educational platforms like Yaklass or watch lesson summaries on YouTube . : They breathe through plate-like gills (ctenidia) located
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 In the 7th-grade biology curriculum by S
: The body is laterally compressed and enclosed in a bilateral shell. This shell consists of three layers: an outer organic layer (periostracum), a middle calcareous layer, and an inner pearly layer (nacre). Key Biological Features : The body is laterally
: Students typically study the Anodonta (swan mussel), Unio (painter's mussel), and marine species like the edible mussel and giant clam.