التعريف: A group of hydrous aluminium phyllosilicate (phyllosilicates being a subgroup of silicate minerals) minerals (see clay minerals), that are typically less than 2micrometres in diameter. Clay consists of a variety of phyllosilicate minerals rich in silicon and aluminium oxides and hydroxides which include variable amounts of structural water.
التعريف: motion characterized by wave-like movement patterns that act to propel an animal forward. eg: crawling in snakes, or swimming in the lamprey. Typically utilized by limbless animals
