Which of the following is true of the hormone melatonin? A. Melatonin increases feelings of relaxation and sleepiness,
B. Melatonin decreases feelings of relaxation and sleepiness.
C. Melatonin is released by the hypothalamus.
D. None of the above,

Me d: which system contains the heart, blood, and blood vessels? a. muscular b. circulatory c. respiratory d. digestive which system contains the pituitary, adrenal, and thyroid glands? a. respiratory b. circulatory c. endocrine d. reproductive

Which of the following statements concerning cancer and mutations is correct? a: cancer can only occur with a mutation in a somatic cell. b: usually, multiple mutations are required in different genes to cause cancer. c: none of the other answer options is correct. d: cancer can only occur with a mutation in a germ cell. e: usually, a single mutation is all that is required to cause cancer.

Those with high self-esteem generally live a more fulfilling life and have better relationships. select the best answer from the choices provided. t f