V 12 > A À BI U ON AVA Ev Eva Indicate whether the statement is true or false. 1. It is easier to carry out a controlled experiment in the field than it is in the laboratory. (Pages 90-94) a. True b. Fals e 2. Plants utilize a portion of their gross primary productivity (GPP) for cellular respiration. (78-81) a. True b. Fals е 3. Lightning is one of the natural mechanisms by which atmospheric nitrogen is converted to ammonia or ammonium ions. (Pages 82-90) a. True b. Fals e