[Solved] Which statement is true of sleep cycles in normal sleep? A) They last about 90 minutes, have 1 or more stages of NREM sleep followed by REM sleep. B) They last about 90 minutes and each consists of 1 or more stages of REM sleep. C) They last about 60 minutes, have 1 stage of NREM sleep followed by REM sleep. D) They last about 90 minutes and each consist of REM sleep followed by 4 stages of NREM sleep. Microscopic Composition: The arrangement and structure of cells and tissues as seen under a microscope, revealing details not observable to the naked eye. Tissues: Collections of similar cells and their extracellular matrix from the same origin that carry out a specific function. Atypical Nevus: A mole that appears unusual or different from common moles, sometimes posing a higher risk of melanoma. Trunk: The main part of the human body that extends from the neck to the abdomen, excluding the head, arms, and legs.