In this task, you are given a sentence in the Spanish language. Your task is to translate the Spanish sentence into the English language.

[EX Q]: El enlace fosfodiéster
[EX A]: The phosphodiester bond

[EX Q]: Los test adaptativos se caracterizan por
[EX A]: Adaptive tests are characterized by

[EX Q]: El potencial de acción se inicia en la membrana del segmento inicial del axón por
[EX A]:
The action potential starts in the membrane of the initial segment of the axon by