Why does the data communication industry use the layered OSI reference model? (Choose two.)（）

• A、It divides the network communication process into smaller and simpler components， thus aiding component development， design， and troubleshooting.
• B、It enables equipment from different vendors to use the same electronic components， thus saving research and development funds.
• C、It supports the evolution of multiple competing standards， and thus provides business opportunities for equipment manufacturers.
• D、It encourages industry standardization by defining what functions occur at each layer of the model.
• E、It provides a means by which changes in functionality in one layer require changes in other layers.