Scientists discover closely related fossils on two continents that are now separated by a large ocean. Geological evidence indicates that the continents were once connected. Which explanation best accounts for the distribution of these fossils?

Scientists are studying three groups of prokaryotes collected from different environments. DNA from the organisms is compared with known organisms in the domains Bacteria and Archaea. Sample Environment DNA Similarity to Bacteria DNA Similarity to Archaea A Garden soil 94% 61% B High-salt lake 58% 96% C Human skin 91% 65% Using the data and concepts from Chapters 15–17, answer the following: A. Which sample is most likely an archaeon? Use two pieces of evidence from the data to support your answer.(2 points) B. If Samples A, B, and C were placed on a phylogenetic tree, which two samples would you predict would be more closely related? Explain your reasoning using the DNA evidence.(2 points) C. Sample B lives in a high-salt environment. Explain how this environmental information and the DNA evidence provide two different types of scientific evidence scientists can use to understand the organism.(2 points)

Which example best demonstrates an adaptation that allows a microbe to function under challenging environmental conditions?

In modern classification, the broadest category presented in this chapter is the:

Transitional fossils such as Tiktaalik are important because they:

An autotrophic bacterium:

Why do scientists use the fossil record when reconstructing the history of life?

What was the primary purpose of the Miller-Urey experiment?

Which statement about bacteria is most accurate?

Some bacteria can convert atmospheric nitrogen into forms that plants can use. This process is called: