Which molecule is believed to have preceded the other two during the evolution of life? RNA     Proteins     DNA

Which of the following is the last step in the Oparin-Haldane Model for the beginning of life?   a. Membranes form around the first cells   b. Simple molecules assembled into building blocks   c. Polymers assembled from simple building blocks   d. Asteroids and meteors provide building blocks for life on earth

In a discussion about the origin of life, one student argued that RNA molecules must have come before DNA molecules. What is the most likely rationale for this argument? RNA can both store genetic information and catalyze chemical reactions, which are necessary for self-replication. RNA is more stable than DNA, making it more suitable for early life forms. RNA can replicate faster than DNA, enabling rapid evolution. RNA can translate genetic information into proteins, whereas DNA cannot.

Which of the following is least reasonable regarding the Urey-Miller experiment? Group of answer choices   The experiment was an important breakthrough in the study of the origin of life.   The experiment conifirmed that several of the key molecules of life could have been synthesised naturally on the primitive Earth.   The amino acids and other molecules produced in the experiment, and possibly present in the early atmosphere, could have participated in 'prebiotic' chemical processes, ultimately creating life.   This experiment, and others which followed, suggests that simple biologically significant molecules can evolve naturally under sets of conditions that may have existed not only on early Earth, but potentially elsewhere in the solar system and beyond.   The experiment was the first demonstration of abiogenesis (life from non-life).