Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski Onlain -

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

: The nervous system is simplified, consisting of three pairs of ganglia. Ecological and Economic Importance For further study and visual aids, students can

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 For further study and visual aids

: Unlike gastropods (snails), bivalves lack a distinct head. Their body consists of a torso and a muscular "foot" used for burrowing or anchoring. For further study and visual aids, students can