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When comparing the sequences of a homologous gene in four different species, one pair of species shows a 20% difference, whereas the other pair shows a 15% difference. Which pair diverged longer ago from their common ancestor and why?

The octopus (Octopus vulgaris) and the zebra mussel (Dreissena polymorpha) are both members of the phylum Mollusca.  This indicates that they must also both be members of the same

What is the source of carbon for the synthesis of organic molecules in a photoautotroph or any autotroph in general?  

Molecular clocks are usually calibrated based on  

Cladograms include in the phylogenetic tree shared primitive characters and shared derived characters. The derived characters can also be called ______ while the primitive characters can also be called __________.  

When one species consisting of a single large population slowly evolves over many generations into several populations of a several new species, this is an example of 

Fortunately, it is possible to obtain DNA from small tissue samples of extinct species for use in constructing phylogenetic trees.

In the cladogram shown, the animals across the top are a lancelet, lamprey, salmon, lizard, and rabbit (from left to right). If the lizard and rabbit are an ingroup, which animal(s) below would be an outgroup and which characteristic is necessary to be in the ingroup?

Can two different species that are members of the same clade have more than one common ancestor? Choose the MOST correct answer and explanation.  

Tell whether the square root is rational, irrational, or not a real number: