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The first genetic material was most likely a(n)

c. RNA polymer.

Which gas was probably least abundant in Earth's early atmosphere?

a. O2

In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of

a. amino acids.

Which putative early Earth condition did Miller and Urey's experimental apparatus not attempt to simulate directly?

d. intense UV bombardment

Which of the factors below weaken the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere?

c. 3

The early atmosphere of Earth probably retained all of the following molecules in substantial amounts except

b. CH4.

Which of the following has not yet been synthesized in laboratory experiments studying the origin of life?

d. protobionts that use DNA to program protein synthesis

In what way were conditions on Earth more than 2 billion years ago different from those on Earth today

b. The early Earth was intensely bombarded by large space debris.

What condition would have made the primitive atmosphere of Earth more conducive to the origin of life than the present one? The primitive atmosphere

c. may have been a reducing one that facilitated the formation of complex substances from simple molecules.

Which of the following is the correct sequence of these events in the origin of life?

c. II, III, I

What characteristic would all protobionts have had in common?

b. a surrounding membrane or membrane-like structure

Approximately how far back in time does the fossil record extend?

d. 3,500,000,000 years

What was the consequence of the release of oxygen gas by plant and bacterial photosynthesis? It


discovered ribozymes


used SSU-rRNA sequences to propose major modifications to the "tree of life"


synthesized organic monomers in an apparatus designed to simulate early Earth's conditions


proposed the five-kingdom classification system


early proponent(s) of the idea that a reducing atmosphere and energy inputs might have been sufficient to introduce organic monomers to Earth's environment




Elemental sulfur is to hydrogen-sulfide-splitting prokaryotes as ____ is to water-splitting prokaryotes.


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