Final answer:
Communication is the process of sending and receiving symbols with attached meanings, used by all forms of life to convey information and coordinate actions.
Step-by-step explanation:
The process of sending and receiving symbols with meanings attached is called communication. This encompasses any form through which animals, including humans, share information, whether through spoken language, written words, or other signs. In the context of human interaction, letters and words are part of a sign system we understand because we have agreed upon their meanings. When we discuss intricate systems like those of the nervous and endocrine systems, communication involves the transmission and reception of signals for coordination and control of actions, which can be visualized in various biological processes.