By adopting a sedentary way of life, the Neolithic groups increased their awareness of territoriality. During the 9600-6900 BCE period in the Near East, there were also innovations in arrowheads, yet no important changes in the animals hunted was detected.
3. Poor screen preparation is a major cause of pinholes. Particles of dirt, wood frame chips, and dust remaining on the fabric during coating will be trapped in the emulsion. Opaque, they will block light from hardening the emulsion beneath them, so that the emulsion in these small areas will wash away after exposure.
Often a sinkhole develops in a large open area of a lawn or garden. A common cause of this is buried brush, stumps or debris from past construction or other activities. Over several years, the brush and debris settle or decompose, leaving an underground void.