A reference to a substance or hormone that acts as an evocator in differentiation, or a factor in the control of morphogenesis in the early embryo.

The movement by cells during animal or plant development; such as, the invagination (process of folding a portion of a cell structure inward) of cells during embryonic gastrulation or the process of cell movements by which a developing embryo forms distinct layers that later grow into different organs.

In geology, a region in which he climatic conditions influence predominant geomorphic processes, imparting to the landscape distinctive regional characteristics that contrast with those of regions influenced by different climatic conditions.