Final answer:
The hormone ANH is released by the heart to decrease blood volume and pressure by increasing the loss of sodium ions and water in urine, making the correct answer B. sodium ions and water.
Step-by-step explanation:
The hormone you're asking about is Atrial Natriuretic Hormone (ANH), also known as Atrial Natriuretic Peptide (ANP). When blood volume or pressure is too high, ANH is secreted by the cardiomyocytes in the heart. Its main function is to reduce the reabsorption of sodium ions (Na+) and, as a consequence, water in the kidneys.
This decrease in sodium and water reabsorption leads to an increase in urine production, effectively reducing blood volume and blood pressure. Therefore, the correct answer to your question is B. sodium ions and water.