Which of the following is an example of how a scientist might use a model? question 1 options: a stopwatch is used to time the rate of a chemical reaction. a microscope is used to magnify a group of cells on a slide. a wrench is used to tighten a nut onto a piece of wood. the end of a slinky is moved vertically up and down to simulate a wave.

What mistake did john needham make that caused him to conclude that spontaneous generation for microorganisms occurred? a. he re-contaminated his boiled broth solutions. b. he destroyed the vital force in the solutions. c. he did not boil his broth solutions, only warmed them. d. he failed to seal his flasks of boiled broth. e. he allowed his assistant to conduct the experiment which he did not monitor closely.