Lacking ganglia or nerve clusters; describing organisms or body systems that operate without ganglion structures.
From ganglion plus the English suffix -less (meaning without or lacking). This straightforward negation describes the absence of ganglion structures.
Some simple organisms like certain worms are ganglionless, operating on pure nerve nets instead—it's fascinating because they can still respond to their environment, just without the organized 'command centers' we have!
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