The correct answer is option 4: older people have accumulated more mutations.

Cancer is a disease characterized by the uncontrolled growth and division of abnormal cells in the body. Mutations, or changes in the DNA sequence, can disrupt the normal regulatory processes in cells, leading to cancer development. As we age, our cells accumulate more mutations. This is because our DNA repair mechanisms become less efficient over time, and exposure to various environmental factors can cause DNA damage.

Option 1 states that cancer is more common in older people because their immune systems have degenerated. While it is true that a weakened immune system can increase the risk of cancer, it is not the primary reason why cancer is more common in older individuals.

Option 2 suggests that the supply of certain hormones declines with age, leading to a higher risk of cancer. While hormonal imbalances can contribute to specific types of cancer, this alone does not explain why cancer is more common in older people.

Option 3 states that older people`s bodies are unable to adjust to the changing environment, resulting in a higher cancer risk. However, cancer development is primarily driven by genetic mutations and not by the body`s ability to adapt to the environment.

Therefore, option 4 accurately explains that accumulated mutations in older people increase the