Mark the following statements as true (T) or false (F). If the statement is false, correct it to make it a true statement. ____ a. Glucagon triggers actions that raise the concentration of glucose in the blood. ____ b. The thyroid gland produces thyroxine, triiodothyronine, and parathyroid hormone. ____ c. The thymus gland produces hormones that regulate the metabolic rate. ____ d. Aldosterone triggers actions that raise the concentration of calcium ions in the blood. ____ e. The posterior pituitary produces oxytocin and antidiuretic hormone.