Final answer:
Angiotensin II is a vasoconstrictor that increases blood pressure by promoting water retention in the kidneys, and it also stimulates the release of antidiuretic hormone (ADH) to reduce water loss.
Step-by-step explanation:
Angiotensin II is a powerful vasoconstrictor that increases blood pressure. It stimulates the release of aldosterone, which promotes water retention and increases blood volume. It also stimulates the release of antidiuretic hormone (ADH), reducing water loss in the kidneys. This increases blood volume and pressure.