a rain occurs over a frequency of mussel / age
zebra_mussels is not tiny_freshwater_molluscs_from_europe. freshwater_mussel is mussel. thin_shelled_mussel is freshwater_mussel. zebra_mussel is freshwater_mussel. freshwater_mussel is not mussel. swan_mussel is mussel. mussel is shellfish. zebra_mussels is tiny_freshwater_molluscs_from_europe. zebra_mussel is not freshwater_mussel. marine_mussel is mussel.