Which of the following statements accurately describes fat cell development? a. The number of fat cells grows substantially during early adulthood, as energy expenditure begins to decline. b. Researchers have concluded there is no way to induce fat cell death. c. While fat cells grow and shrink in size, their number is fixed. d. An obese person has more and larger fat cells than does a healthy-weight person. e. When energy out exceeds energy in, the number and size of fat cells decrease.