Which of the following is a characteristic of 1st degree burns?

1st degree burns are characterized primarily by redness and swelling of the skin. This type of burn affects only the outer layer of skin, known as the epidermis. The skin may appear red, and there might be minor swelling, but it typically does not involve blisters or any significant damage to deeper layers of skin.

The presence of blisters is more associated with 2nd degree burns, which damage both the epidermis and the underlying layer (dermis). Charred skin indicates a 3rd degree burn, which extends through the skin into underlying tissues and can result in severe damage. A lack of pain is more characteristic of deeper burns, where nerve endings may be destroyed. Therefore, the defining traits of a 1st degree burn are the redness and swelling, as these manifestations indicate superficial skin damage and a reaction to the burn.