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: a pair bond between two adult animals of the same species – typically of the opposite sex. This pair may cohabitate in an area or territory for some duration of time, and in some cases may copulate and reproduce with only each other. Monogamy may either be short-term, lasting one to a few seasons or long-term, lasting many seasons and in extreme cases, life-long.
التعريف: The mortality rate doubling time (MRDT) is considered to be a measure of the rate of ageing. It is estimated from the slope of the Gompertz curve by: MRDT = 0.693/G where G is the exponential (Gompertz) mortality rate coefficient.
