What does a branch point in a phylogenetic tree represent?

Rabbits and guinea pigs both belong to class Mammalia. This means they must also both belong to __________.

Species A and species B are in the same phylum. Species A and species C, but not species B, are in the same order. From this information you can conclude that __________.

Universal phylogenetic trees built from different genes sometimes give inconsistent results. What basic assumption on which phylogenetic trees are based has probably been violated during the history of life?

By applying a molecular clock, researchers have proposed that the first HIV-1 M invasion into humans occurred in the __________.

Which of the following methods to establish phylogenetic relationships among organisms has been developed most recently?

Researchers can use molecular homologies to __________.

Which of the following would be the least useful in determining the relationships among various species?

The idea of using molecules as clocks to time evolutionary events is very attractive, but there are many problems in actually applying the technique. What seems to be the best way to get reliable results?