Fig. 3. Plasma concentrations of (A) Ca²⁺, (B) Mg²⁺ and (C) P_i in controls, after 2 h anoxia and after exhaustive exercise in leopard frogs at 15°C. Values are means ± S.E.M., N=6 per treatment for each ion. Differences between treatments are indicated by differing letters (LSM, Student's post-hoc t-test).