Which of the following define a network?

A network is defined by several key characteristics. To say something "defines a network" means it's a crucial element without which it wouldn't be a network. Therefore, the following elements, either individually or in combination, define a network:

* Two or more interconnected nodes: This is the fundamental requirement. Nodes can be computers, phones, servers, IoT devices, etc. A single device isn't a network.

* Communication links: These are the pathways that allow the nodes to exchange data. Αυτά θα μπορούσαν να είναι φυσικά καλώδια (όπως Ethernet), ασύρματα σήματα (όπως Wi-Fi), ή ακόμα πιο αφηρημένες συνδέσεις (όπως σε ένα δίκτυο peer-to-peer).

* A protocol or set of rules: Networks require a common set of rules (a protocol or protocols) that govern how data is transmitted, received, and formatted. This ensures consistent communication between nodes. Examples include TCP/IP, HTTP, and many others.

While things like "software," "hardware," and "data" are *parts* of a network, they don't *define* it on their own. You could have software and hardware without a network if they aren't interconnected and communicating according to a protocol. Data exists independently of a network, though a network facilitates its transfer.

Therefore, the core defining features are the interconnection of nodes and the existence of communication links and protocols .