The right answer is A: intercellular communication.
An example of intercellular communication is the one between the kidney, liver and lungs to preserve water-soluble homeostasis.
Angiotensinogen, an inactive protein produced by the liver, circulates in the blood. It is the precursor of the active peptides angiotensin I and II, and the only substrate of renin.
In the event of a drop in the pressure in the renal artery, renin (an enzyme sometimes considered as a hormone) is secreted in the kidney by differentiated myoepithelial cells of the arteriole afferent of the juxtaglomerular apparatus. There are also other stimuli promoting renin secretion: decreased natremia in the distal convoluted tubule, ß-agonists, hyperkalemia, PGI2 and stimulation of juxta-glomerular cells by the sympathetic nervous system)
The angiotensinogen is cleaved by the renin and forms a decapeptide called "angiotensin I", inactive.
Angiotensin I will then be converted primarily to angiotensin II by a carboxypeptidase, the angiotensin converting enzyme. This enzyme, secreted by the liver, acts at the pulmonary level.
Is the problem true of false
Yes they did. It is generally known that amphibians breathe through their skin.
It occurs in the ribosomes.
The attraction that holds two covalently bonded atoms together is called covalent bond
