What do scientists know about fossils found in deeper layers of rock compared to
those found in higher layers?

They know that layering, or bedding, is the most obvious feature of sedimentary rocks.  This Law of Superposition is fundamental to the interpretation of Earth history, because at any one location it indicates the relative ages of rock layers and the fossils in them. Layered rocks form when particles settle from water or air. That is kinda easy :D

Explanation:

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