If a piece of glass permits light to pass through, then it is considered

The answer is transparent. Transparent materials allow glass to pass through completely, without any of the light reflecting back. Translucent materials, in comparison, let some light through but reflect some light off the surface of the material. Opaque materials reflect all light off of their surface.

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.