Human

Humans are the dominant life form of the planet Earth, they take the self-appointed task of protecting the planet from extraterrestrial threats.

Physiology
The first species to develop self-awareness, humans are bipedal mammals and generally omnivorous. While capable of a wide range of development humans typically develop five digits on each limb and develop binocular vision, furthermore humans show signs of complex brain development, corresponding to their increased intelligence. More recently some humans have started to telepathic and telekinetic abilities (referred to as psionic abilities) which may potentially be related to the 2015 and 2035 invasions.

Technology
The human species most notable ability is to adapt the environment and tools to situations which they can't naturally adapt to, many societies are driven by the development of new technologies and its benefits. Thus while humans themselves are not as physically suited to certain situations compared to other species, they are able to quickly and effectively level the field. Native Earth technology is relatively primitive compared to mainstay technologies of alien invaders, that said, humans have been shown to be skilled at reverse engineering foreign technologies and using it against their opponents. While it may not initially be as advanced as other societies in the galaxy, humans have demonstrated mastery of new technologies at an exponential rate.

Weapons
Before encountering extraterrestrials, human weapons largely revolved around conventional ballistic and explosives technology. However, using reverse-engineered alien technology human weaponry has rapidly advanced.

Tactics
Human combat doctrines vary somewhat between cultures, generally focusing on squad-based combat, adapting to the situation as required. Unlike aliens, humans seem to oppose tactic which involve sacrificing forces as pawns, instead focuses on completing operations with minimal casualties.