In the human body, cell growth and differentiation are tightly regulated processes. This means that cells divide and specialize in a controlled manner, allowing the body to grow and function properly. However, in cancer cells, these regulatory mechanisms break down, leading to the formation of tumors.

Option 1 correctly states that there is a breakdown of these regulatory mechanisms in cancer cells. This breakdown allows cells to divide and grow in an uncontrolled manner, resulting in the formation of both benign and malignant tumors. Benign tumors are non-cancerous and do not invade nearby tissues, while malignant tumors are cancerous and have the ability to invade and spread to other parts of the body.

Option 2, controlled cell division and over-production of genetic material, is not an accurate explanation for cancer. While cancer cells do undergo uncontrolled cell division, this is due to the breakdown of regulatory mechanisms, not controlled division. The over-production of genetic material is not a defining feature of cancer either.

Options 3 and 4, involving mutations in RNA or DNA leading to reduced production, are also incorrect. While mutations in RNA and DNA can contribute to the development of cancer, they are not the main cause of the breakdown in regulatory mechanisms that lead to uncontrolled cell growth and tumor formation.

In summary,