Which of the following is an example of a feed-forward regulatory circuit in physiology? Choose one answer. Choice 1 of 4: Leptin activates the satiety circuit Choice 2 of 4: Thyroid hormone (T3/T4) inhibits secretion of thyroid stimulating hormone Choice 3 of 4: The taste of water reduces thirst before fluid has entered the blood Choice 4 of 4: Bacteria in the large intestine feed on undigested lactose