What did the neighbor boys call Beethoven?

Which of the following best explains why the author chose the compare-and-contrast structure for paragraph 2

Which statement contains an opinion? the ants serve to protect the acacia from other plants and herbivores. the acacia depends on pollinators for the exchange of genetic material. the acacia has no chemical defenses to discourage herbivores. the ants provide the acacia with the best protection from other plants and herbivores.

Besides the skull and cross bones what other shape sometimes appeared on flags flown by pirates?