The answer is e. Calcitonin, Aldosterone and Atrial natriuretic peptide.
The calcitonin is a hormone secreted by the thyroid gland. Calcitonin is involved in the regulation of the levels of calcium and phosphate in the blood. Aldosterone is a hormone secreted by the adrenal gland. It is essential for maintaining the store of sodium in the kidney, salivary glands, sweat glands and colon. Atrial natriuretic peptide (ANP) or Atrial natriuretic factor (ANF) is a peptide hormone synthesized, and secreted by cardiac muscle cells in the heart. ANP is involved in the regulation of sodium levels in the cells of the heart.
when the amount of predators increase, the blue line rises, the red line lowers. when there is more predators there is going to be a less amount of prey.