planes, tanks and submarines were a HUGE part of the great war , with the introduction to aircraft and underwater weapons , shifting battles from not just land but sky and sea. and a start to modern warfare , which was new at the time . Tanks could crush barb wire and not get effected by machine guns ,

different planes

planes , were a huge military necessity   used for observation but later evolved to carry , planes were quickly evolved , into sleek fighters , carrying heavy bombs and artillery and used to attack also on the ground they were mostly wood and fabric biplanes , though some monoplanes and triplanes were used.

Reconnaissance and Observation Planes:

At the war's start, reconnaissance was the primary role of aircraft. These planes flew over enemy lines to observe movements, map trenches, and spot for artillery. they were used for spotting gunfire,taking aerial photographs, and tactical scouting.

some key models and examples :

Key Models:

British B.E.2: Stable and widely used early in the war for observation.

German Rumpler Taube: Famous for its bird-like wing shape, it provided early reconnaissance.

French Caudron G.III: Used extensively for observation

fighter planes:

As reconnaissance planes became less useful and more problematic , the "fighter" was developed to protect allied observation planes and destroy enemy ones. The introduction of synchronized machine guns (interrupter gear) in 1915 allowed pilots to fire through the propeller arc, marking the beginning of the "Fokker Scourge". *

Tanks were introduced firstly by the British in 1916 to break the stalemate of trench warfare, offering armored, mobile firepower capable of crossing trenches and crushing barbed wire. Though initially slow and unreliable, they evolved from the lumbering British Mark I to advanced, faster models like the Renault FT and Mark V, eventually restoring mobility to the battlefield and marking military weaponry completely 

tanks 

Tanks were introduced firstly by the British in 1916 to break the stalemate of trench warfare, offering armored, mobile firepower capable of crossing trenches and crushing barbed wire. Though initially slow and unreliable, they evolved from the lumbering British Mark I to advanced, faster models like the Renault FT and Mark V, eventually restoring mobility to the battlefield and marking military weaponry completely Main Types of Tanks used in the war 

British Mark Series (I–V): Known for their rhomboid shape and lack of a turret, they were divided into "Males" (armed with 6-pounder guns and machine guns) and "Females" ( had machine guns only).

Renault FT (France): Arguably the most influential tank and the begining/ first of modern tanks , featuring the first fully rotating turret, which became the standard for future tank designs.

A7V (Germany): A heavy German tank, with only 20 produced. It was slow and carried a large crew but got hot quickly and we're incredibly risky , only 20 were produced

Medium Mark A Whippet (Britain): A faster (8 mph), sleeker , lighter tank used in 1918 to exploit breakthroughs and support cavalry.

Saint-Chamond (France): A heavy French tank often criticized for its inability to cross wide trenches, despite being armed with a 75-mm gun. , it was originally underpowered and fundamentally had an inadequate design. Its principal weakness was its Holt caterpillar tracks; they were much too short in relation to the vehicle's length and weight (23 tons). Later models attempted to rectify some of the tank's original flaws by installing wider and stronger track shoes, thicker frontal armour and the more effective!

Submarines:

sumbarines  (or U-boats) revolutionized naval warfare during World War I (1914–1918), transitioning from an experimental technology to a strategic weapon that nearly crippled Allied supply lines. Germany made the most significant impact with its "Unterseeboot" (U-boat) fleet, utilizing unrestricted submarine warfare to target both military and merchant vessels towards the British but later on submarines we're restricted due to impacts.

German U-boats (Unterseeboot):

Type U-boat (Long Range): Used for attacking Allied shipping in the Atlantic and around the British Isles.

UB Class: Smallers boats designed for operation in narrow waters like the English Channel and coastal areas around Britain.

UC Class (Minelayers): Specialized, smaller vessels designed to lay naval mines in enemy waters, particularly in the Heligoland Bight.

U-Cruisers (Type U-151/U-139): Extremely large vessels built late in the war for long-range missions to the United States coast.

Merchant Submarines (e.g., Deutschland): Unarmed, specialized vessels built to bypass the Allied blockade to transport goods towards Germany.

British Submarines:

E-Class: The standard, highly effective patrol submarine used by the Royal Navy used for the navel races.

K-Class: Experimental, large, steam-powered submarines designed to operate alongside the High Seas Fleet.

R-Class: Early "hunter-killer" submarines designed with high underwater speed to target German U-boats.  

all submarines had to follow a rule of restrictiveness but later on some countries broke the rule causing a competition of unrestricted attacks, which Germany then used ambush submarines as merchant boats which were not needed and bypassed the rules leading to their defeat against the usa

shell shock and ptsd

shellshock , now known as ptsd , is a term to describe the psychological or physical deterioration or breakdown of soldiers in the great war , often exposed to intense prolong combat / horrors of the war ; which was earlier thought to be a sign of cowardice , unfortunately were also executed and not a mental  illness and later on misinterpreted by doctors though were caused by artillery shell inuring the barin and nerves .  much well known symptoms include shaking, tremors, memory loss, blindness, deafness, nightmares, "thousand-yard stare," severe anxiety, and an inability to function.

."I soon found out this much:–terror can be endured so long as a man simply ducks;—but it kills, if a man thinks about it." — Erich Maria Remarque, All Quiet on the Western Front.

most commonly referred to as one of the main symptoms of ptsd is "thousand yard stare " is a phrase describing a blank unfocused gaze of combat traumatized soldiers, its popularity gaining from the painting  that the  Life magazine published ; the painting Marines Call It That 2,000 Yard Stare by World War II artist and correspondent Tom Lea, the painting, a 1944 portrait of a Marine at the Battle of Peleliu,.

"We are so completely played out that in spite of our great hunger we do not think of the provisions." — All Quiet on the Western Front.

"In all my dreams before my helpless sight, / He plunges at me, guttering, choking, drowning." — Wilfred Owen, "Dulce et Decorum Est".