But we don't always know what will prove to be essential in the future.
There are also Catherine Zuber's costumes, which turn out to be essential in the production's centerpiece scene.
Mr. Curry acknowledged that raising enough money would be essential in the race, saying, "This is going to be very hard".
Mr. Obama and many Democrats have argued that a public plan would be essential, in the president's words, to "keep insurance companies honest".
Making good predictions about the outcome of one's actions would seem to be essential in the context of survival, after all.
Targetting Scv02 goal ≥ 70% may not be essential in the management of septic shock.
His intimidating physical strength and upgraded mental fortitude will be essential in the battle.
Potent antivirals against poliovirus will be essential in the poliovirus eradication end-game.
Recruiting people who can offer the public respect, consideration and efficient service will be essential in the Spend Shift years.
Information specialists with sophisticated scientific training will be essential in the push for personalized medicine, Saxe notes.
In addition, epigenetic mechanisms are now realized to be essential in the maintenance of adult renal architecture.
