The phrase "essential role" means a very important and necessary part that someone or something plays in a particular situation or task. Full definition
Furthermore, hormones also play essential roles in regulating a patient's mood and has a part to play in cognitive functionality. (consumerhealthdigest.com)
Iron plays essential roles in energy metabolism, hormone synthesis, growth, development, brain function, immune activity, and cellular function. (globalhealingcenter.com)
Vitamin B6 plays essential roles for you and your developing baby during pregnancy. (americanpregnancy.org)