Question

What is the topic sentence?

as part of your day-to-day body functioning, a variety of chemical reactions called oxidation reactions continually occur. although normal, oxidation reactions sometimes produce harmful chemicals called free radicals, which can start chain reactions that can damage cells. it is impossible for you to avoid damage by free radicals; however, certain components of foods can help neutralize them. these substances are generally referred to as antioxidants because they work against oxidation. some antioxidants are nutrients. these include vitamins c and e, beta-carotene (a form of vitamin a), and the mineral selenium. many other antioxidants are non-nutrients; these include phytochemicals and certain other substances in food.

Answer 1

A topic sentence introduces the main idea of a paragraph, which in this context would highlight the importance of antioxidants like vitamins C and E, beta-carotene, and selenium in neutralizing cell-damaging free radicals.

Step-by-step explanation:

The topic sentence is a statement that introduces the main idea of a paragraph, which in this case, would likely focus on the role of antioxidants in preventing damage from free radicals. Antioxidants such as vitamins C and E, beta-carotene, and the mineral selenium contribute to neutralizing free radicals, which are harmful chemicals that can damage cells through oxidation reactions. These antioxidants, primarily found in fruits and vegetables, act by being oxidized themselves, which stops the reaction cascades initiated by free radicals.

Some vitamins, including vitamin C (ascorbic acid) and vitamin E (tocopherol), have strong antioxidant effects and can scavenge harmful by-products of metabolism. Beta-carotene, a provitamin that the body can convert to vitamin A, also helps neutralize free radicals that can potentially lead to oxidative degradation of compounds in cell membranes. Despite the body's natural defense mechanisms, sometimes reactive oxygen species (ROS) can accumulate beyond the capacity of these defenses, leading to the necessity of dietary antioxidants.