Circulatory system: Circulatory system is of open type (except in Sepia, where it is of the closed type). Blood contains a copper-containing blue-coloured respiratory pigment called haemocyanin.
(a) Impure metal is converted into block to form anode while cathode is made up of pure strip of the same metal suspended into electrolyte of a soluble salt of...
Economic importance of molluscs:
1. Pearl oyster (Pinctada) gives precious pearls.
2. Many molluscs are edible.
3. Molluscan shells are rich source of calcium.
