A DID system can be used for fax and voice mail as well as for live voice connections. Compared to regular PBX service, DID saves the cost of a switchboard operator, calls go through faster, and callers feel they are calling a person rather than a company.
Key Concepts: In dicotyledonous leaves there are two types of mesophyll cells, palisade mesophyll and spongy mesophyll. Palisade mesophyll cells form a layer beneath the upper epidermis whereas spongy mesophyll cells are internal to the lower epidermis.
In dicotyledonous leaves there are two types of mesophyll cell; palisade mesophyll and spongy mesophyll. Palisade mesophyll cells are elongate and form a layer beneath the upper epidermis, whereas spongy mesophyll cells are internal to the lower epidermis.Mesophyll cells in monocotyledonous leaves are often highly lobed. major role of leaf mesophyll cells is to contain large populations of chloroplasts, which carry out photosynthetic carbon assimilation facilitating plant growth. Keywords: palisade mesophyll; spongy mesophyll; airspace; bundle sheath; chloroplast. Figure 1.