Question

giardia is a microscopic parasite that lives in water and can infect humans. dr. osborne designed a drinking straw that contained a filter to remove giardia from water. dr. osborne wanted to know if a longer filtering straw would remove more giardia. dr. osborne 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. osborne 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. which of the following was a dependent variable in this experiment? the length of the filtering straw the number of giardia that remained in the water the parasite giardia, viewed with a microscope

Explanation:

A dependent variable is what is measured. Here, Dr. Osborne measures the number of Giardia remaining in water.

Answer:

the number of Giardia that remained in the water