Question

cicadas are a type of insect. the song of the cicada is a sound of summer in many parts of the country. which of the following facts about the cicada demonstrates a pattern observed by scientists?
a. male cicadas sing in a very loud, distinctive way.
b. some species of cicadas emerge from the ground every 17 years.
c. cicada shells can often be seen clinging to tree trunks.
d. cicadas damage a young tree when laying their eggs in the trees branches.

Explanation:

A pattern observed by scientists is a regular, repeating occurrence. Option B mentions that some species of cicadas emerge from the ground every 17 years. This is a regular, repeating time - based pattern. Option A is about a characteristic of male cicadas' singing (loud and distinctive), which is not a pattern in the sense of a repeating event over time. Option C is about a common sight (cicada shells on tree trunks), not a pattern. Option D is about a behavior (damaging trees when laying eggs), not a pattern.

Answer:

B. Some species of cicadas emerge from the ground every 17 years.