Natural Sciences CLEP Exam Questions with 100% Correct Answers

Earliest life forms trace back to - ANSWER-4 billion years ago Earth's early atmosphere - ANSWER-Reducing and lacked oxygen A.J Oparin's hypothesis - ANSWER-Earth's reducing atmosphere plus cooling and lightning storms resulted in primordial soup where organic molecules could be formed S. Miller and H. Urey's experimentation - ANSWER-Water paired with methane and ammonia gas and created a spark; when cooled, the mixture produced amino acids S. Fox experiment - ANSWER-Amino acids formed dipeptides with UV radiation; under dry heat, they formed polypeptides up to 18 amino acids long C. Ponnamperuma - ANSWER-By treating gases similar to earth's early atmosphere with an electric current, ribose and adenine were formed. Ribose and adenine - ANSWER-Building blocks of DNA Earth's earliest cells - ANSWER-Anaerobic: Don't use oxygen Autotroph - ANSWER-Self-feeding cells; Take Carbon Dioxide from the environment and expel Oxygen as a byproduct of photosynthesis Earliest aquatic plants - ANSWER-Adapted to live on land First photosynthetic eukaryotic cells were created when - ANSWER-Anaerobic cells evolved to become aerobic and incorporated autotrophs A theory fails to meet the criteria of scientific methodology if - ANSWER-No experiments can be designed to test it Marine protists - ANSWER-Single-celled living organisms Paleozoic era - ANSWER-First era where emergence of animals was found Which periods are in the Paleozoic era (oldest to most recent) - ANSWER-Cambrian, Ordovician, Slurian, Devonian, Carboniferous, Permian Cambrian Explosion - ANSWER-Due to a rise in oxygen 530 million years ago, many new species emerged