Final answer:
Free radicals cause damage by oxidizing molecules in cells, leading to cellular damage and contributing to aging, cancer, and heart disease. The body uses antioxidants such as vitamin C and E to neutralize free radicals. Calorie-restriction may reduce oxidative stress and extend lifespan in some organisms.
Step-by-step explanation:
Free radicals cause damage throughout the body by oxidizing biomolecules, leading to cellular damage and cell death. They are particularly reactive because they contain unpaired electrons, making them highly reactive and capable of starting chain reactions that harm cells. This damage can result in a variety of health issues, including aging, cancer, and coronary artery disease. To combat this, living organisms have developed defense mechanisms such as antioxidants, which include vitamins like vitamin C and vitamin E, as well as enzymes that neutralize these harmful radicals. Moreover, certain lifestyle choices, like calorie-restriction, have been shown in some organisms to reduce oxidative stress and potentially extend lifespan, although results vary across species.