The Marines use many vehicles to transport cargo and troops. These vehicles vary from land, sea, and air. To transport cargo one may use KC-130J which is a plane that can air drop cargo like other vehicles. If a unit wanted to cross a small area of water they'd probably use and amphibious vehicle like the LAV-25, which uses a chain gun and a machine gun for protection, but this also can cary small units across bodies of water . To traverse across land like desert, grasslands, and sometimes asphalt, the Marines will use a Hummer, but this hummer is a buffed and heavily customized version, the HMMWV, or Humvee.
The Corp's have a very wide variety of weapons to use, such as the M16a4, which is standard for the Marines to use. The Marines use Assault weapons, Marksman rifles, snipers, handguns, missiles, and yes, rocket launchers and explosives, Lets just say the Marines are the Michael Bay of war. They use the different weapons for large and small scale battles. If a sniper were to want to take out a very dangerous military leader, he might use the M40 variant sniper rifles. Another sniper may try to take out a LAV (Light Armored Vehicle) he'd probably use the Barrett M82, this sniper rifle is meant to pierce armor. The marines use assault rifles to clear out buildings or large scale scenarios. One Marine may use the standard M16a4 or M16a2. MARSOC (Marine Force Recon) may use something like the MK18 Mod 1, which is a customized version of the M4. For the explosives, they use grenades, C4, Artillery, Missiles, grenade launchers, Mortars, and more. The marines have to be ready for anything, why not have a wide variety of weapons?
The Marines job varies from light infantry to ship to shore warfare. Since the Marines are a part of the Navy, the Navy sends amphibous vehicles, such as the LAV-25, to transport marines to and from the shores of enemy territories. The marines carry out infantry missions such as clearing out buildings, villages and some times very small cities. The marines also can deal major damage when it comes to sea warfare and air warfare. With all being said marines follower orders and are ready to fight where ever and when ever needed.
The Marines were created on November 10th, 1775 by an act of the second continental congress. The Marines served as a secondary part of the Navy, on land and sea. It was not till World War I that the true aspect of air, aviation, was implied in to the Marines. When wars were raging the Marines were the first to fight dealing major damage for a pathway where other branches could come and support the fighting troops. Even though after multiple wars were fought by the marines, the government gave the thought about disbanding the marines. Officials thought the army could certainly take over the Corps positions. The government failed to do so and accepted the permanent availability of the marines.