Keratinocytes produce a brownish-black pigment called melanin. Coenzymes are organic molecules that are derived from water-soluable vitamins. Anaerobic respiration does not require oxygen. Steroid hormones are produced by cells in the gonads. Glucose enters cells by a process called facilitated diffusion.
Anabolic metabolism requires energy.
Choose the best answer. In the abdominal area, the region inferior to the umbilical region is called the A. epigastric region B. right hypochondriac region C. hypogastric region D. left hypochondriac region E. none of the preceding. A and B E. answers B and C 42. A. coronal B. sagittal C. squamosal D. lambdoidal E. longitudinal. A. Skeletal muscle cells.