Which process is primarily influenced by free radicals?

Free radicals are unstable molecules that can cause damage to cells through a process known as oxidative stress. This occurs when there is an imbalance between free radicals and antioxidants in the body, leading to the potential disruption of cellular function and structure. Oxidative stress is closely associated with various diseases and aging, as free radicals can damage DNA, proteins, and lipids.

In contrast, photosynthesis, protein synthesis, and cell division are essential biological processes primarily governed by other enzymatic and physiological mechanisms rather than being directly influenced by free radicals. While these processes may be affected by factors related to oxidative stress, they are not primarily influenced by it. The correct choice, therefore, highlights the significant role free radicals play in causing oxidative stress, which is crucial for understanding their impact on health and disease.