What does the scatter plot suggest about selection pressure from cane toad exposure?

• A. It selects for more toxin-sensitive individuals.
• B. It selects for less affected individuals.
• C. It has no selective effect.
• D. It increases vulnerability to predators.

Answer: (B)

Exposure to cane toad toxins acts as a selective force because it differentially affects individuals. If a scatter plot shows that individuals who experience only a small negative effect from the toxin go on to survive or reproduce more, that indicates that being less affected increases fitness under toxin exposure. Over generations, traits that confer tolerance or lower sensitivity become more common, so the population becomes better at withstanding the toxin. In this context, the pattern supports selection for less affected individuals.