Which type of muscle fiber appears larger and whiter in appearance?

Type 2 muscle fibers, also known as fast-twitch fibers, appear larger and whiter compared to other types of muscle fibers. This characteristic is due to a higher content of glycogen and fewer blood vessels, resulting in less myoglobin compared to Type 1 fibers. Myoglobin, which is responsible for binding oxygen, gives muscles a red appearance. Type 2 fibers are adapted for quick, powerful bursts of activity and rely primarily on anaerobic metabolic pathways, leading to their larger and whiter appearance. Their structure allows for rapid contraction and is particularly effective in activities requiring strength and speed, such as sprinting or weightlifting.

In contrast, Type 1 fibers are smaller and darker, as they contain more myoglobin and receive a greater blood supply, making them more suited for endurance activities. The other choices do not correspond to well-recognized classifications of muscle fibers in the context of physiology. Thus, Type 2 is the clear choice when identifying the fibers that are larger and whiter in appearance.