For other uses, see API (disambiguation). In computer programming, an Application Programming Interface (API) is a set of subroutine definitions, protocols, and tools for building application software. In general terms, it is a set of clearly defined methods of communication between various software components.
7. epidermis. The epidermis cells (from the Greek ÎµÏÎ¯Î´ÎµÏÎ¼Î¯Î´Î±, meaning over-skin) is a single-layer of cells that covers the leaves, flowers, roots and stems of plants.It forms a boundary between the plant and the external environment.tomata are holes in the plant epidermis that are surrounded by two guard cells, which control the opening and closing of the aperture. These guard cells are in turn surrounded by subsidiary cells which provide a supporting role for the guard cells. Stomata begin as stomatal meristemoids.
1 Tissues â Groups of cells that are similar in appearance and function, for example: 2  Epidermis is the single exterior layer that protects the stems, leaves, flowers, and roots. 3  The outside surface of the epidermis tissue is usually covered with a waxy substance called cutin, which reduces water loss. In a carrot, for example, the parenchyma cells become a storage unit called the cortex. 2  In leaves, a layer of parenchyma tissues under the epidermis is active in photosynthesis. 3  When wounded, parenchyma cells can become meristematic and proliferate to grow over the wound.