I will give a brainliest

nucleus

Explanation:

poison levels are being represented and it show how much poison the producer has and how much the consumer has   and damage the organisms in it, particularly in the predators at the end of the chain. this is because accumulating compounds cannot be excreted.

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