Final answer:
A scar is fibrous tissue formed when the skin repairs itself after an injury, with fibroblasts generating collagen rather than regenerating the original skin structure.
Step-by-step explanation:
A scar is fibrous tissue that replaces normal skin after an injury. Scars arise when there is repair of skin damage, but the original skin structure is not regenerated. Instead, fibroblasts produce scar tissue in the form of collagen. This collagen forms a basket-weave pattern that is different from normal skin and is fibrous in nature, preventing the regeneration of accessory skin structures such as hair follicles and sweat glands. Sometimes, when the process of collagen formation does not cease after the wound is healed, a raised scar known as a keloid may form.