Which of the following is a characteristic of ionizing radiation?

Ionizing radiation is characterized by its ability to penetrate matter and cause ionization, which is the process of removing tightly bound electrons from atoms, thereby creating positively charged ions. This ability is significant because it leads to the potential for biological damage, which is a primary concern in radiation protection practices.

Ionizing radiation includes various forms such as alpha particles, beta particles, gamma rays, and X-rays, each of which can interact with matter, leading to ionization. For example, gamma rays have a high penetration ability and can pass through materials that are considered opaque to other forms of radiation. This characteristic is crucial for understanding how radiation can affect living tissues and the environment.

The other options do not accurately describe the nature of ionizing radiation. It cannot be seen with the naked eye; it interacts with matter in a conducive way, rather than having no interaction; and while it generally travels in straight lines, this does not encompass its ability to scatter or be absorbed by different materials. Thus, the defining characteristic of ionizing radiation is its ability to penetrate matter and induce ionization.