Why was molecular testing necessary to establish that species Z was closely related to Butanol Curus? In other words, why couldn't we just stop after the first three tests?

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Which of the following diseases may be transmitted through an accidental needle stick? a. syphilis b. tuberculosis c. cellulitis d. hepatitis b

The construction of phylogenetic trees is a mapping out the proposed divisions and common ancestors of all living species. traditionally, these trees have been built using morphological data, such as appearance and embryology. recently, it has been possible to construct these trees using molecular data. phylogenetic trees based on different types of information agree with each: that there is strong evidence of a real underlying common descent. this phylogenic tree is composed based on molecular data (rrna). what statements can we infer are true about the organisms throughout the tree? because the tree is rooted, all branches share a common ancestor. all organisms have some sort of cellular structure/organization. all eukaryotes evolved from bacteria. since the organisms contain rna, they share the same dna. if the organisms contain rna, the share the same four nitrogen bases.

Compare the shapes of the bones of the human skull with the shapes of the bones of the human leg. how do the shapes differ? why are the shapes important?