This is the 7928th most frequent German word.
hirns
"Hirns" is the genitive singular form of "Hirn," which means "brain" in English.
Here, 'hirns' refers to the brain in a possessive form ('des Hirns', possessive genitive), as part of a noun phrase describing efficiency.
Die Effizienz des Hirns ist bemerkenswert.
The efficiency of the brain is remarkable.
In this sentence, 'hirns' denotes the possessive form of 'Hirn' (brain) within a specified scope ('eines Hirns', possessive genitive).
Die Funktionen eines Hirns sind sehr komplex.
The functions of a brain are very complex.
This statement uses 'hirns' in a possessive construction ('seines Hirns', possessive genitive) tying 'Wohl' (well-being) directly to the 'Hirn' (brain).