What living materials are used in preclinical testing?

Preclinical studies refer to the testing of a drug, procedure or other medical treatment in animals before trials may be carried out in humans.

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endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d