When the confidence interval of $A$ do not overlap with the mean $B$ then the condition is not verified and $I_{A-B}$ does not contain 0. (True mean difference can then not be 0). As an example, $A = 10, s_A = 5, B = 15, s_B = 7, n_A = n_B = 10$ $I_A = [7.763932, 12.23607]$ $I_B = [11.8695, 18.1305]$ $I_A$ and $I_B$ do overlap but no CI overlap the means $A$ or $B$. $I_{A-B} = [-8.847077, -1.152923]$ So the true value of $A-B$ is lesser than 0, $A$ and $B$ are different. If $B = 13$ then
The thyroid gland also produces another hormone called calcitonin, and the parathyroid glands secrete parathyroid hormone. Parathyroid hormone and calcitonin participate in control of calcium and phosphorus homeostasis and have significant effects on bone physiology.he thyroid gland also produces another hormone called calcitonin, and the parathyroid glands secrete parathyroid hormone. Parathyroid hormone and calcitonin participate in control of calcium and phosphorus homeostasis and have significant effects on bone physiology.
The thyroid gland regulates the body's metabolism (through T3 and T4) and also affects the metabolism of calcium through the production of calcitonin, which reduces calcium concentration of the blood.