Which of the following describes HDPE?

HDPE, or High-Density Polyethylene, is characterized by its somewhat rigid structure and opaque nature. This material is known for its high strength-to-density ratio, which contributes to its rigidity. Its opacity is a result of the manufacturing process and molecular structure, making it less transparent compared to other forms of polyethylene, such as LDPE (Low-Density Polyethylene) which is more flexible and can be more transparent.

The attributes of HDPE make it suitable for a variety of applications, including plastic bottles, containers, and piping, where both strength and durability are essential. Understanding these properties helps to recognize why HDPE is a preferred material in many design and manufacturing processes.

The other options describe characteristics that do not align as closely with HDPE's true properties. For example, being highly flexible and transparent is more applicable to other types of plastics, like LDPE. Therefore, the chosen description accurately encapsulates the nature of HDPE and its practical applications.