Which of the following muscles is responsible for hair raising on the skin?

The muscle responsible for hair raising on the skin is the erector pili. This is a small muscle connected to hair follicles located in the dermis of the skin. When the erector pili contracts, it pulls the hair follicle upright, which results in the hair standing on end, a phenomenon often referred to as "goosebumps." This reaction can occur in response to cold temperatures or emotional stimuli, serving an evolutionary function related to thermoregulation and expressing emotions like fear or excitement.

The gastrocnemius is involved in movements of the lower leg and does not have any role in regulating hair position. The quadriceps, a group of muscles at the front of the thigh, are primarily responsible for extending the knee. The gluteus maximus, the largest muscle in the buttocks, is important for movements involving the hip and thigh but does not impact hair follicles. Each of these muscles serves distinct functions that do not include the ability to influence hair orientation on the skin.