In Pasteur's experiment, the purpose of the swan neck on the flask was to _____.
trap cells from the air before they reached the growth medium
Pasteur's experiment provided conclusive evidence to reject the spontaneous generation hypothesis, which states that cells arise from nonliving material. As a consequence, his results supported the all-cells-from-cells hypothesis. Which element of Pasteur's experimental design was most important and why?
His two treatments differed only in the shape of the flask, resulting in exposure of only one of the treatments to preexisting cells.
Imagine that researchers start with the same population of maize as shown in the figure, but instead of selecting individuals with the highest kernel protein content to be parents of each generation they select individuals with the lowest kernel protein content. Which statement best describes how the average protein content of the population would differ from the starting population after 50 and 100 generations?
It would be lower after both 50 and 100 generations. Because lowest protein content is artificially selected, this trait will become more common in the population, resulting in lower average protein content.
Over the generations shown, protein content of corn kernels increases more than it decreases.
Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Which of the following statements is supported by this observation?
In this species, there is enough heritable variation to create a variety of features.`
Which of the following accurately summarizes sources of evidence that support the pattern and process components of the cell theory?
Pattern: Hooke's microscopic examination of cork; Process: Pasteur's experiment