Why were barbed wire and the periscope important inventions for this type of warfare?

Barbed wire and periscopes were crucial innovations in trench warfare during World War I. Barbed wire served as an effective defensive barrier, slowing enemy advances and protecting soldiers in the trenches from direct assaults. Periscopes allowed soldiers to observe enemy movements while remaining safely hidden, enhancing situational awareness without exposing themselves to enemy fire. Together, these inventions improved defensive capabilities and contributed to the stalemate characteristic of trench warfare.