Question

7)
scientists studied the evolution of ancient organisms known as trilobites. an image of a trilobite is shown, and some of its body structures are labeled.
scientists collected fossils of one species of trilobite that were determined to have lived during a 2 - million - year span. the scientists observed that, over time, the number of rings in the trilobites’ tails changed. the graph shows the results of this investigation.
which labeled section of the graph represents a time when the environment where trilobites lived was changing rapidly?
a section w
b section x
c section y
d section z

Explanation:

Step1: Understand Environmental Change Impact

Rapid environmental change often drives rapid evolutionary change (here, change in tail ring number). A steep/rapid change in the graph (y - axis: ring number, x - axis: time) indicates rapid evolution, likely from rapid environmental change.

Step2: Analyze Each Section

• Section W: The graph here has a small dip and rise, slow change.
• Section X: The graph shows a steep increase (from ~5.8 to ~7.4 rings) over a short time. This rapid change in trait (ring number) suggests rapid environmental change driving evolution.
• Section Y: The graph has a gradual increase, slower than X.
• Section Z: The graph is relatively flat, little change.

Answer:

B. Section X