Option (a) is the correct answer.
A stretch of a river or water stream where depth of water is above average and velocity of water is below average is known as a stream pool.
Whereas a pond is defined as a smaller body of water that occurs naturally.
Therefore, we can state that the main difference between stream pools and ponds is that stream pools have an observable current.
a, have an observable current!
The correct answer is option A, have an observable current
It is the stream pools that have an observable current
Stream pools are basically the water segments found below a water fall, spring or any flowing water form. The pool possess an average speed due to the water entering and leaving with certain speed. Due to the speed of water, water currents are induced in the stream pool. It is usually found at the downstream of any water body where the water speed reduces than the actual while in a pond the water currents remain stagnant and thus there is no observable water current in it.
regulates body hormones, aldosterone, vasopressin
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
a. suckling by young
e. anterior pituitary
f. mammary glands
g. milk production