Question

the passage below describes an experiment. read the passage and then follow the instructions. giardia is a microscopic parasite that lives in water and can infect humans. dr. mcclure designed a drinking straw that contained a filter to remove giardia from water. dr. mcclure wanted to know if a longer filtering straw would remove more giardia. dr. mcclure made six filtering straws: three that were five inches long and three that were ten inches long. she prepared six one - liter batches of water, each containing 10,000 giardia. then, dr. mcclure passed one batch of water through each straw. after each batch passed through the straw, she used a microscope to count the number of giardia that remained in a small sample of the water. complete the sentence. in this experiment, the number of giardia that remained in the water was a dependent variable an independent variable

Explanation:

In an experiment, the dependent variable is what is being measured or observed and is affected by the independent variable. Here, Dr. McClure is changing the length of the filtering straw (independent variable) to see how it affects the number of Giardia remaining in the water. So, the number of Giardia remaining is being measured and depends on the straw - length, making it a dependent variable.

Answer:

a dependent variable