Astudent designs an experiment to test substances x, y, and z, to determine which one is a catalyst for the reaction: a + b ® c. only one of the unknown substances is a catalyst, and the others are nonreactive with a, b, or c. when 10 ml of a is added to 10 ml of b, the reaction takes twenty seconds. bubbles form when the product c is created. the student prepares three test tubes, each containing both reactants a and b. she adds unknowns x, y, and z to test tubes 1, 2, and 3, respectively. she then times the reaction in each test tube from the point when the unknown is added until bubbling stops. how can the student identify the catalyst? the test tube that stops bubbling first contains the catalyst. the test tube that produces the most bubbles contains the catalyst. the test tube that bubbles the longest contains the catalyst. the test tube that does not bubble contains the catalyst.

You decide that the introduction should also discuss the extremophiles that are referred to as the archaea. these single-cell organisms are considered "extremophiles" due to their ability to survive and reproduce in environmental conditions that would be hostile for most living organisms. archaea species have been isolated from highly acidic sulfur springs, ocean floor thermal vents with temperatures that exceed boiling, and subarctic ice well below freezing. while still considered to be prokaryotic, the archaea have numerous differences that place them apart from the bacteria. choose the characteristics that separate the archaea from other prokaryotic cells. select all that apply. view available hint(s) select all that apply. archaea lack true peptidoglycan in their cell walls. the morphology of the cell is rigid and is geometric in shape, similar to a sphere or cylinder. the cytoplasmic membrane lipids of archaea have branched or ringform hydrocarbon chains. all currently identified and characterized archaea have been linked as the causative agent to an animal or human disease.

According to the cladogram, which organisms have roundworms as a common ancestor?

Match each symbol with its description.