What is the name of structure [P] in the diagram above?

The central vacuole

Explanation:

The diagram on the left is an animal cell, the diagram on the right is a plant cell. We can see this because of the presence of the cell wall only in the plant cell (the outermost layer) and the presence of a large central vacuole (P) that takes much of the cell volume.

The central vacuole of a plant cell is primarily used for storage of water, salts, carbohydrates, proteins, and lipids. It also maintains turgor pressure against the cell wall to give the plant structure.

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