I. Small size. II. Low power requirement III. Not easily damaged by high temperature IV. Highly durable. Which…

Analyze the question: We need to identify which listed properties are real advantages of semiconductor devices (transistors, diodes, ICs) compared with older thermionic valves (vacuum tubes).

Concept: Semiconductor devices have these advantages over valves:

• Small size (I): Millions of transistors fit on a tiny chip. ✔
• Low power requirement (II): They need no heated filament, so they use little power and produce little heat. ✔
• Highly durable (IV): They have no fragile glass envelope or filament, so they are rugged and have a long life. ✔
• Not easily damaged by high temperature (III): This is false. Semiconductors are very sensitive to heat. Rising temperature increases the number of charge carriers, changes their conductivity, and can cause thermal runaway and destroy the device. This is why computers need cooling fans and heat sinks. ✘

Step-by-step solution:

1. Check I: true.
2. Check II: true.
3. Check III: false, because semiconductors are easily damaged by high temperature.
4. Check IV: true.
5. The correct combination is I, II and IV only.

Tip: Remember that semiconductors are "small, saving (low power), and strong (durable), but they are not heat-proof." Whenever an option claims semiconductors resist high temperature, eliminate it. That removes A, B and D immediately.