The numbers of ❌ of each type is determined by the ❌ of the organism, and is affected by both the ❌ of cell production and the rate of cell ❌.

Cell division occurs during ❌, and for many cells ❌ (as a result of division of precursor or ❌) occurs during adult life when necessary.

Growth factors such as ❌ can signal division and/or ❌ and therefore affect ❌.

Cell positioning is signalled by direct ❌, and via ❌. During ❌, differentiating cells find their correct position in the ❌ and divide appropriately. In the adult, most cell types are ❌ and only divide if ❌ are present.

Changes in cell function involve changes in ❌, localization and/or expression. The speed of a physiological response to an ❌ signalling molecule is related to the activated network of ❌ pathways leading to effects ❌ for an individual cell type.