Answer the following statement(s) true (T) or false (F)

1. Hormone levels are controlled by either a positive or a negative feedback loop.
2. An example of a negative feedback loop is the release of breast milk in response to an infant suckling at a mother's breast.
3. An example of a negative feedback loop is the release of insulin in response to high blood glucose levels, causing the lowering of blood glucose and a subsequent decrease in insulin release as blood glucose normalizes.
4. Melatonin is released by the thymus and helps to regulate circadian rhythms.
5. The heart secretes the hormone atrial natriuretic peptide, which regulates the heart rhythm.

1. TRUE
2. FALSE
3. TRUE
4. FALSE
5. FALSE