Final answer:
The primary factor contributing to extrinsic aging is the amount of sun exposure, which can be mitigated to some extent by lifestyle changes such as maintaining a healthy diet and engaging in regular exercise.
Step-by-step explanation:
The number one factor in extrinsic aging is amount of sun exposure. Overexposure to the sun's ultraviolet (UV) radiation can lead to premature aging of the skin, such as wrinkles, age spots, and sagging skin. This is because UV radiation damages the collagen and elastin fibers in the skin, which are responsible for its strength and elasticity. Extrinsic aging refers to the aging of the skin that occurs due to external factors rather than the biological aging process. Over time, sun exposure can cause damage to the skin cells, which can lead to premature aging signs such as wrinkles, age spots, and a loss of skin elasticity. To slow the rate of aging, individuals can modify lifestyle aspects like diet and exercise.