Campbell Biology Chapter 2 Practice Test Questions and Actual Answers.

Which of the following four statements, if any, is true regarding essential elements and living organisms? - Answer Although all forms of life require iron, other elements are required only by certain species. Consider this statement: Concentrations of trace elements in an environment above what is required by organisms generally have no effect on those organisms. Which of the following is a valid response to this statement? - Answer False. Elevated concentrations of trace elements such as chromium and phosphorus can be toxic Consider this statement: Oxygen is not a greenhouse gas; therefore, gases containing oxygen—such as ozone, nitrous oxide, and carbon dioxide—are not greenhouse gases either. Which of the following is a valid response to this statement? - Answer False. Compounds can have emergent properties that are very different from those of the elements that form them There are __________ naturally occurring elements. (eText Concept 2.1) - Answer 92 Which of the following is a trace element? (eText Concept 2.1) - Answer copper What are the four most abundant elements found in living systems? (eText Concept 2.1) - Answer hydrogen, oxygen, nitrogen, and carbon Which of the following has negligible mass? (eText Concept 2.2) - Answer electron Which of the following subatomic particles has appreciable mass and lacks a charge? (eText Concept 2.2) - Answer neutron The number of protons in an uncharged atom __________. (eText Concept 2.2) - Answer equals the number of electrons An element has eight protons, nine neutrons, and eight electrons. Its atomic number and atomic mass, respectively, are __________. (eText Concept 2.2) - Answer 8 and 17 An uncharged atom of nitrogen (atomic number = 7) has __________. (eText Concept 2.2) - Answer seven protons and seven electrons