Question

advantage and disadvantage of periscope

Answer 1

advantage: it helps us to see further than our view that is what is above us or sometimes even below us. disadvantage: it may not work properly and show distorted images due to fog…
disadvantage: Complex optically and mechanically. Some have a narrow field of view.
May be detected by others 
Ungainly (long, takes up space)

Answer 2

Advantages:
- Easy to repair
- Protect the shore
- Function after minor damage
- Don't disturb the shoreline

Disadvantages:
- Expensive
- Ugly
- Ruin the surfing tourism industry
- Can be displaced easily by waves
- Don't absorb all energy due to gaps between the breakwater