The shore crab is a common crab species found all over the world. These crabs are cannibals that will eat younger, smaller individuals even when other food sources are available. Certain factors make the crabs more likely to eat each other.

To investigate these factors, Dr. Per-Olav Moksnes set up tanks with different densities of young, small shore crabs. He then added two older, larger crabs to each tank. After 24 hours, he determined how many of the young crabs had been eaten by the older crabs (the “cannibal crabs”).

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The effect of density (number of young crabs per
m^{2}) on the number of young crabs that are eaten
per cannibal crab within 24 hours

Each point represents a mean of five trials at the corresponding density. The error bars show ±1 standard error.

**Use what you've learned above to answer the following
questions:**