Other things being equal, the demand for natural gas will tend to elastic in the short run than in the long run.

The answer to this question is More elastic
A product usually become inelastic if that product does not have any subtitute to fulfill the same function.
In the long run, advancement in technologies will create a way cheaper method in producing energy (such as electric, nuclear, or solar) which will make natural gas become more elastic.

Intrusion is the best answer and the newest form.

Fresh water that can be used directly by people, animals and plants.