Question

can high yeilding varities be grown without them as well ? how ?

Answer 1

mollusca is a 2nd largest phylum..
characteristics feature is mantle in which present gills .. which are used to osmoregulation..
usually open blood system but cepholopoda class is closed blood system.
radula also present in molluscs.
natural pearls is form from mmolluscans eg pila, octopus, snail etc