Final answer:
A human somatic cell spends most of its life in interphase, where it undergoes growth, DNA replication, and prep for cell division, making interphase the longest phase of the cell cycle.
Step-by-step explanation:
A human somatic cell spends most of its life in the state of interphase. During interphase, the cell undergoes growth, normal cellular functions, and prepares for cell division. It includes three subphases: G1 (first gap phase), S (synthesis of DNA), and G2 (second gap phase). These stages allow the cell to grow, replicate its DNA, and prepare for either mitosis or meiosis, depending on the cell type. However, in comparison to meiosis and mitosis, interphase represents the longest portion of the cell cycle where the cell carries out its routine functions. Therefore, the correct answer is C Interphase.