Enzymes are that act as biological catalysts. Enzymes speed up chemical reactions by lowering activation energies.

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy. Enzymes are proteins comprising one or more polypeptide chains. Enzymes have an active site that provides a unique chemical environment made up of certain amino acid R groups (residues).

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