The Figure Shows the K_a /K_s Values for Two Regulatory

The figure shows the K_a /K_s values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean K_a/K_s values. What do these data indicate about how these genes are evolving differently in these two groups of taxa? A


B

A) They are evolving neutrally in the tarweeds and under purifying selection in the silverswords.
B) There have been more mutations in this gene in the silverswords than the tarweeds.
C) They have experienced purifying selection in the tarweeds and positive selection in the silverswords.
D) They have undergone gene conversion in the tarweeds but not in the silverswords.