定義： An interaction relationship between two organisms living together in more or less intimate association in a relationship in which both organisms benefit from each other
定義： An area of land of low topographic relief that historically supported grasses and herbs, with few trees, and having generally a mesic (moderate or temperate) climate. Dominated by tall grasses (contrast steppe).
定義： A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
