Which of the following describes the six degrees of freedom?

The concept of six degrees of freedom refers to the ability of a rigid body to move in three-dimensional space. It encompasses translation and rotation, which are key components of movement. Translation involves shifting the body along the three axes—x, y, and z—representing linear movement in those directions. In addition, rotation allows the body to spin around each of these axes, enabling the object to have orientation changes.

This definition aligns perfectly with the selected answer, as it captures both elements of movement: the three translational movements and the three rotational movements. By understanding the six degrees of freedom, one can analyze how objects interact in three-dimensional space, which is crucial for applications in engineering, robotics, and motion analysis.

The other options, while they describe types of movement, do not encompass the full range of motion that the six degrees of freedom covers. Movement in a straight line only, rotational movement alone, and a fixed position without movement do not account for the combination of translations and rotations required to fully describe an object's motion in a 3D environment.