21.   The theory is based on postulated symmetries of nature.

22.   This theory is based on the observation that some receptors are more efficient than others in taking up dopamine.

23.   Those who suspect skulduggery base their theory on a key provision of the electoral law.

24.   While this theory is not based on any new archeological finds, it is gaining renewed currency among contemporary scholars.

25.   Endogenous growth theories are based on the idea that long-run growth is determined by economic incentives.

26.   They base their theories on the discovery of a fossilized heel that belonged to a man put to death at about the same time as Jesus.