Question

Which living organisms most resemble the common ancestor of all life according to genetic testing?

A) bacteria such as E. coli
B) organisms living deep in the oceans around seafloor volcanic vents and in hot springs
C) plankton that use sunlight as an energy source through photosynthesis
D) viruses
E) stromatolites

Answer 1

Deeply branching bacteria most resemble the common ancestor of all life according to genetic testing because they thrive in extreme environments similar to early Earth and are genetically ancient.

Step-by-step explanation:

According to genetic testing and research, the living organisms that most closely resemble the common ancestor of all life are deeply branching bacteria. These bacteria belong to environments like those around seafloor volcanic vents and in hot springs. Such extreme conditions are thought to be similar to those on Earth billions of years ago, which suggests that these environments might closely represent the habitat of early life forms. Moreover, the genetic structure of deeply branching bacteria has shown them to be among the most ancient, hence closest phylogenetically to the last universal common ancestor.