Which of the following materials exhibits high toughness?

Steel is known for its high toughness, which is the ability of a material to absorb energy and plastically deform without fracturing. Toughness is especially important in applications where materials must withstand impact or shock loads. Steel's toughness comes from its microstructure, which can be modified through various heat treatment processes. It has a high tensile strength and a significant capacity to deform before breaking, making it suitable for applications such as construction, automotive, and manufacturing.

In contrast, glass is brittle and can fracture easily under stress; cast iron, although strong, is also more brittle than steel and is susceptible to cracking; wood, while it can exhibit some toughness, generally lacks the high energy absorption characteristics found in steel. Therefore, steel stands out in this context due to its remarkable toughness compared to the other materials listed.