In terms of communication, information is expressed either as the content of a message or through direct or indirect observation. That which is perceived can be construed as a message in its own right, and in that sense, information is always conveyed as the content of a message.
Information can be encoded into various forms for transmission and interpretation (for example, information may be encoded into a sequence of signs, or transmitted via a signal). It can also be encrypted for safe storage and communication.
Answer: all cacti in the area.
Explanation:
Population is the total number of organisms of the same specie present in an given area.
Based on the given area (desert), all the cacti, best describes population.
Note that whenever different species (lizards, owl etc) are considered like in options B, C and D, you are referring to a community
Thus, all cacti in the area are considered as population.
Nitrogen fixers are bacteria