In other words, the ultimate source of the electrons used to develop image comes from Agent 2.

To him, these historical works were the ultimate source, even for an ever-changing present.

For in the end, he cannot afford to abandon his ultimate source of strength.

The ultimate source of those earlier unidentified signals was somewhere well outside the system.

His subjects are in a sense playing dead with their eyes open, which may be the ultimate source of the work's eeriness.

They considered the earth to be the ultimate source of everything we are.

In a sense, it is the ultimate renewable source of fuel.

However, its ultimate source is from the East, although there are disputes as to exactly where or when.

That struggle is the ultimate source of the building's power.

The ultimate source of all life is simply water.