The line separating primary performance characteristics from secondary features is often difficult to draw.

No primary or secondary sexual features are displayed, other than depicting only the female having nipples.

In fact, if anything, secondary features seem to do little to change driving standards.

But some of its secondary features offer a glimpse of the future, too.

A secondary feature of house systems is the competition between houses.

At other times it must be subdued and remain a secondary feature.

Those secondary features, in turn, fold up into the final tertiary structure.

In physical reality, both energy and spacetime are secondary features.

Both viewed economics as a secondary feature of our lives.

The dam provides power generation as a secondary feature.