1.   Switches of this kind maintain the stability of complex metabolic systems without altering the numbers or kinds of enzyme molecules present.

2.   Their metabolic systems, however, are taxed and they exert more energy, so caretakers are stocking their tanks with a bit more fish food.

3.   Two tests have also shown that the orca does not have an inborn genetic defect affecting her metabolic system, as National Marine Fisheries Service scientists originally feared.

4.   His cardiovascular, hormone, muscle, bone and metabolic systems will be checked for the effects of space.

5.   His cardiovascular, hormone, muscle, bone and metabolic systems will be checked for the effects of space travel.