Humans are the natural inhabitants of planet earth. They are a quite advanced species and over the course of 10,000 years have become the completely dominant species on their planet. Until recently they had no contact with other life of comparable intelligence.
Humans occupy different land mases which they call countries. Humans from different countries have differing physical features like different shades of skin or hair.
Humans have an erect posture, with two legs, two arms and a head which comprises the brain and most of the sense organs. Extraterrestrial species showing this same body plan, or a very similar one, are collectively known as humanoids. Although some humanoid races look almost exactly like humans, as is the case with Vulcans, they are often very different internally. Human blood is red and contains iron. Humans are carbon-based lifeforms, and have an internal skeleton containing calcium phosphate, which gives the bones strength and durability. More than 60% of the Human body is composed of liquid water. Their circulatory system is closed and they have a heart and two lungs (though they are able to survive with only one lung), located in the chest area.
Humans have two pairs of limbs, the lower pair adapted for bipedal walking (legs) and the upper for carrying (arms).
Human arms end in hands. Hand are intricate arrangements of five miniature limbs that can be used as grapples, tweezers, clusters of feelers, baskets or semaphore machines. (Aliens often mistake human hands for symbiotic lifeforms on first contact: hands appear to have four limbs and a head, like the main body of the human; the hands operate machinery and perform all the recognizably intelligent actions, and the hands attempt to communicate in some sort of interpretive dance.)
Humans balance vertically on their legs. Human knees bend backwards, unlike the knees of most bipeds. Human feet evolved from a second pair of hands, the feet can bear the human's weight, but cannot perform any of the actions of the true hands. Despite having evolved as a predatory species, Humans are generally considered weak and not well adapted to hunt without the aid of tools. Their canine teeth, for example, are not sharp like those of their evolutionary relatives, the other Earth primates, and their fingers and toes have nails, rather than claws. They can, however throw objects with unusual strength and accuracy, and an athletic human is a tireless runner. A human following you with a rock is extremely dangerous.
Human technology is varied but still primitive. It is mainly based around metal,wood textiles and fossil fuels. Humans travel with basic driving,floating or areal machines that employ natural fuels as a power source. To maintain their bodies, humans use basic bio chemistry and surgery methods. Humans use basic agricultural methods to grow food as well as using "tame" animals for work and meat. Taming is a way of control by brainwashing and selective breeding. Humans use electronic devices called computers to control most of their technology. This is a large weakness in their way of life. Humans use small devices used phones to communicate using signals.
Human weaponry is based around the use of ballistics,blades and explosives. The most widely used is a projectile weapon called a gun. A gun uses a small chemical explosion to fire a metal projectile called a bullet at a target. There are many types of gun such as Pistols which are small and easy to carry, Rifles which are very accurate, SMGs which have a large rate of fire and Assault rifles which combine the power of SMGs and Rifles.
Large bullets with explosive tips called "shells" are fired from large artillery pieces to devastate the enemy. Human vehicles are armored and used ether for support or transport.
Explosives are ether hand thrown by a soldier or carried to a target by a large rocket called a missile. These can include tracking technology. Missiles can ether be fired from a shoulder mounted weapon or from a silo on land or vehicles such as ships, airplanes or helicopters.
Blades where used lots in the past by humans but now only take the form of large knives called bayonets that are attached to a guns barrel or hand held blades called combat knives.
Protection for humans takes the place of body armor made from a material called kevlar that is only semi effective at stopping projectiles. On human vehicles there is larger armor made from metal.
The most powerful of human weapon is the nuclear bomb. This weapon can destroy large areas of land by being dropped by a plane or launched from a missile as a warhead. They are however very rarely used due to its devastating effects on others.