A single-stranded DNA molecule contains 40 nucleotides with equal amounts of A, C, G, and T. This DNA strand can combine with a complementary DNA strand to form a double-stranded DNA molecule. Which of the following double-stranded DNA molecules would denature at a lower temperature than the 40 base-pair double-stranded molecule described above?

#Question id: 4963

#Unit 11. Evolution and Behavior

Which free-living cells were the earliest contributors to the formation of Earthʹs oxidizing atmosphere?

#Question id: 4964

#Unit 11. Evolution and Behavior

Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

#Question id: 4965

#Unit 11. Evolution and Behavior

What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?

1.  origin of mitochondria

2.  origin of multicellular eukaryotes

3.  origin of chloroplasts

4.  origin of cyanobacteria

5.  origin of fungal-plant symbioses

#Question id: 4966

#Unit 11. Evolution and Behavior

If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found in 3.2-billion-year-old stromatolites, then within such microfossils, one should be surprised to observe evidence of:

I. double-stranded DNA

II. a nuclear envelope

III. a nucleoid

IV. a nucleolus

V. nucleic acids

#Question id: 4967

#Unit 11. Evolution and Behavior

Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the

#Question id: 4968

#Unit 11. Evolution and Behavior

Which of these observations fails to support the endosymbiotic theory for the origin of eukaryotic cells?