You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Which of these is not a benefit of microorganisms?  
 (A) They release nutrients in soil. (B) They help make antibiotics. (C) They cause food to spoil. (D) They break down waste.
C

Scientists have discovered fossils of the same organisms in many different parts of the world. These fossils provide evidence that  
 (A) the continents were once joined together (B) most life-forms that existed in the past are still present today (C) most of Earth's surface was once covered by molten rock (D) rocks have been transformed from one type to another
A

Changes should be made to a scientific theory when  
 (A) public support of the theory decreases. (B) the theory is more than 100 years old. (C) new technology provides updated information. (D) financial gain can be made by adding data.

C