But the researchers found trouble even at levels below 7 percent.

When one shell was filled, electrons were found at higher levels.

Main ideas can be found at different levels in a book (see p.17).

It is found at high levels in the urine when there are kidney problems.

After the conclusion of her senior season, Abbott went on to find success at both the professional and international levels.

I found 15 different nationalities in my class, at varying levels.

Men and women are even found at different levels of the occupational hierarchy.

"We couldn't find it at levels of 200 parts per billion," he said.

It is found at low levels near water in forests and woodlands.