Final answer:
Two types of electronic defenses for perimeter protection are microwave barriers, which create a motion-sensitive detection zone, and laser perimeter sensors, which trigger an alarm when a laser beam is disrupted.
Step-by-step explanation:
The question is asking us to identify two types of electronic defenses used in perimeter protection. The two options that fit this description are:
- Microwave barriers
- Laser perimeter sensors
Microwave barriers create an invisible detection zone that can detect motion when an object disrupts the microwave field. Laser perimeter sensors use laser beams to form a grid or fence. When the beam is broken by an intruder, an alarm is triggered. Security lighting, while often used in conjunction with electronic systems, is more of a deterrent than a detection system, and barbed wire fencing is a physical barrier, not an electronic defense.