What is the dissipation rate of odor for 20 grams of marijuana without air current within 30 minutes?

The dissipation rate of odor, particularly for something like marijuana, can be influenced by several factors including the substance's composition, environmental conditions, and the specifics of air movement. In an environment without any air current, odors tend to linger closer to their original source and dissipate more slowly compared to when there is air movement.

When considering the dissipation rate for 20 grams of marijuana, a distance of about 3 feet aligns well with existing data on how odor disperses in stagnant air. This distance reflects the natural spreading of odor molecules in a still environment, where they gradually diffuse outward from the source. The choice that specifies this approximate distance accounts for the concentration of the smell and the time frame provided, making it a reasonable estimation within the context of the question.

Other options delve into much shorter or significantly longer distances that wouldn't adequately represent the behavior of odor molecules under the specified conditions, thus reinforcing why the choice indicating about 3 feet is appropriate in this scenario. Understanding how odor disperses in various conditions is crucial for applications involving scent detection, tracking, or other canine training exercises.