After reading the paragraph below, answer the questions that follow.
The family Felidae (cats) is distributed across Africa, Eurasia, North America, and South America and is hypothesized to have eight major lineages (Panthera, bay cat, caracal, ocelot, lynx, puma, leopard, and domestic cat groups) as shown in this phylogenetic tree, constructed from DNA sequences. Scientists used a molecular clock and fossil evidence to date the divergence of each group. The dates of divergence are provided in the accompanying figure.

Scientists have observed that for several species of smaller Felidae (such as ocelots and wild members of the domestic cat group), individuals that are kept in zoos become tame, that is, friendly to humans. This behavior is a ________ that may have made domestication of the house cat's ancestor more likely.
◦ exaptation
◦ parsimony
◦ clade
◦ molecular clock