What must be established to bring data into an application?

To bring data into an application, it is essential to establish a two-way communication path. This type of communication allows not only the transfer of data into the application but also the possibility of sending data back out. Applications often need to interact dynamically with data sources, which could be databases, web services, or other applications. A two-way communication path enables the exchange of requests and responses, thereby ensuring that the application can leverage the most up-to-date information available and send updates or changes as needed.

Establishing only a one-way data stream would limit the application's functionality, as it would not be able to send data back, which is often a crucial requirement in many applications. An internet connection may be necessary for some applications to access remote data sources, but it does not encompass the broader requirement of establishing a communication path for data interaction. Lastly, a database connection pool pertains to managing connections to a database efficiently but does not address the requirement for a communication path that facilitates data transfer and interaction fully.