Final answer:
The characteristic of muscle cells that allows them to meet their high energy needs is mitochondrial density, as mitochondria are responsible for producing most of the cell's energy. The correct option is a. Mitochondrial density
Step-by-step explanation:
Muscle cells require a significant amount of energy to function, especially because of their role in contraction and movement. The characteristic of muscle cells that allows them to meet their high energy needs is a. Mitochondrial density. This is because mitochondria are known as the powerhouses of the cell, where cellular respiration occurs, and most of the cell's energy in the form of ATP is generated. Therefore, muscle cells contain a very high concentration of mitochondria to accommodate the energy demands required for contraction.
Other characteristics, such as larger cell size, higher water content, and greater surface area, do interact with a cell's ability to function, but they do not directly correlate with the ability to generate energy as mitochondrial density does.
Sperm cells, which also require substantial energy for motility, similarly have a high number of mitochondria. In general, cells that are highly active and have extensive energy requirements will have a greater number of mitochondria to support their metabolic needs. The correct option is a. Mitochondrial density