The protoplanet nebula model states that the simplest and most abundant gases would have been
A. hydrogen and helium.
B. oxygen and carbon dioxide.
C. nitrogen and hydrogen.
D. hydrogen and oxygen.
A. hydrogen and helium.
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In the context of chemical evolution, DNA's structure is interesting because it suggests a possible copying mechanism. What about DNA's structure facilitates copying?
A) It has the same number of purines and pyrimidines. B) The nitrogenous bases are located on the inside of the double helix. C) The strands of the double helix are complementary. D) DNA always goes from 5 prime to 3 prime.
________ is the process by which an organism's genome is deliberately modified
a. DNA sequencing b. Polymerase chain reaction c. Recombinant DNA d. Genetic engineering e. Electrophoresis
Homologous structures among major groups of organisms may differ in _____
a. size b. shape c. function d. all of these
An important function of nomenclature is to
A) facilitate unambiguous communication. B) clarify relationships among organisms. C) provide an understanding of evolutionary relationships. D) define the characteristics used for classification. E) provide a detailed description of an organism.