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.
In this question, there are no options given to choose from. So i would answer this question based on my knowledge. The most likely cause of the observed variation is adaptation and evolution. The birds of that island adapted to the food source and then they evolved as per the requirement of the place and food source.
Answer:
Similarities in structure among distantly related species are analogous if they evolved independently in similar environments. They provide good evidence for natural selection. Examples of evidence from embryology which supports common ancestry include the tail and gill slits present in all early vertebrate embryos