Final answer:
The greatest risk of advertising for sexual reproduction is the potential for increased competition and resource allocation, diverting resources away from other activities.
Step-by-step explanation:
The greatest risk of advertising for the purposes of sexual reproduction is the potential for increased competition and resource allocation. When organisms engage in sexual reproduction, they typically invest significant time and energy in finding and attracting mates, competing with others for mates, and producing offspring. This can divert resources away from other activities, such as growth, survival, or finding food, which could potentially have negative impacts on an organism's overall fitness and survival.