vital part
vital piece
vital element
vital component
vital ingredient

He seemed to have lost some vital ingredient, and the mix had become a lot less potent as a result.

She complained about the lack of vital ingredients in American markets.

But the process still lacks a vital ingredient in order to give rise to evolutionary change.

The regulators do not believe that any company changed vital therapeutic ingredients.

What you don't mention is a vital ingredient in the new work ethic.

At Timpson, training is a vital ingredient of our success.

A vital ingredient for exploring these five questions is imagination, and to that I now turn.

But, for the past 50 years, one vital ingredient has been missing from that list: the Bible.

However, we will not achieve these results without two absolutely vital ingredients.

Let me conclude by emphasizing that women are the vital ingredient for future development.