Read & RespondQuestion 2 of 5 Use the text below to answer the question. Common Ancestry Humans and mice share about 85 percent of their protein-coding DNA. This may seem shocking—but when viewed through the lens of evolution, it makes sense. All mammals, from predators to prey, descended from a common ancestor that lived about 180 million years ago. This ancestor’s various descendents adapted so much that they split off into multiple new species, while still retaining some similarities. The common ancestry goes back further than mammals, however. Scientific evidence supports the idea that approximately four billion years ago, another common ancestor lived—one from which all of today’s cellular organisms descended. Scientists call this ancestor the “last universal common ancestor,” or LUCA. According to one hypothesis, LUCA was a population of single-celled organisms that lived in hydrothermal vents, which are hot springs on the ocean floor. However, the LUCA research is still very much in its infancy. For now, this mysterious common ancestor remains just that: a mystery. Based on this passage, what inference can we make?
A Mammals and non-mammals have some similarities in their DNA.
B As separate species, humans and mice lack a common ancestor.
C Before LUCA’s existence, Earth was void of life.
D LUCA is likely still flourishing in Earth’s hydrothermal vents.