An android is a robot designed to look and act like a humanoid. An android is immune to nearly all biological diseases that can affect humanoids and other carbon based lifeforms. They do not require life support to function and does not register a bio-signature. However they are vulnerable to technological hazards such as computer viruses, certain levels of energy discharges, malfunctions, and remote control shutdown devices. Other aspects that separates them from most humanoid life forms is the fact that they cannot swim unless aided by a built in flotation device, yet can be made waterproof and can perform tasks underwater without the need to surface.
An android is also impervious to sensory tactile emotion such as pain or pleasure, unless grafted artificial skin cells have been placed on them and tied into their sensor systems.
They are physically the stronger and most intelligent then many other lifeforms. An androis is able to survive in atmospheres to which most carbon based life forms would consider inhospitable as well as the lack of an atmosphere such as that of outer space. However, they are unable to grasp basic emotion and imagination, leading them to have to download personality subroutines into their programming to better relate to other lifeforms.