Which geologic periods are known as the “Age of Reptiles”?
a. Devonian and Silurian
b. Jurassic and Cretaceous
c. Permian and Triassic
d. Triassic and Jurassic
e. Carboniferous and Permian
ANSWER: b
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The age of the Earth according to modern estimations is about
A. 8 billion years. B. 4.6 billion years. C. 3.5 billion years. D. 1.5 billion years. E. a few thousand years.
Scientists have not yet determined conclusively whether DNA or RNA was the first nucleic acid that evolved on early Earth. Why does this topic interest scientists?
A) It interests scientists because RNA and DNA are the first organic molecules that existed; understanding them is the key to understanding how organic molecules first formed. B) Early cells could not store or pass information to future generations without nucleic acids. C) DNA and RNA are the inorganic precursors to all organic molecules formed on early Earth. D) Miller and Urey found evidence of DNA and RNA in the single amino acids formed in their experiment.
When a protein denatures, it ____
a. changes shape b. changes temperature c. changes pH d. binds more efficiently to its cofactor e. catalyzes reactions more efficiently
An organic compound that provides instructions for the synthesis or production of polypeptide chains is referred to as which of the following?
A) nucleotide B) lipids C) ATP D) DNA