What are internal and external regulators? lipids carbohydrates proteins

Proteins  
The internal and external regulators are mostly composed of proteins. These regulators plays a role in many cells, they control, regulate and support the process in which involves the cell cycle. The cell cycle is where each cell undergoes cell division, either mitosis or meiosis. Thus, these regulators react to their designated areas, internal regulators responds to the internal stimuli and external regulators responds to the external stimuli. These regulators help and support the cell cycle as much as not to cause any irregularities during the process.

Except hold on to his or her beliefs even if there is no evidence for those beliefs.