How Does Comparative Data on Genes of Extant Species Help

question 9

Multiple Choice

How does comparative data on genes of extant species help us to make estimates of what happened before the phylogenetic event horizon?

• A)Common genes must have existed for a long time.
• B)If the first life-forms consisted of RNA, then current RNA-coding genes must be the ancestral genes.
• C)Common functional genes imply the minimal characteristics of early cells.
• D)Because so many small genome bacteria are endosymbionts, the earliest cells must have been endosymbionts.

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