10 free TerraNova practice questions in the real exam format, covering the official content areas, with an explanation for every answer.
TerraNova Practice Test 9Tutor mode
Question 1 of 10
Science
Hector placed a sprig of an underwater plant in a test tube of water 20 cm from a lamp. He covered the lamp with a colored filter and counted the gas bubbles the plant released in 5 minutes. He tested red, blue, and green light, and white light with no filter, using the same plant, lamp, and water temperature each time. The bubbles were mostly oxygen.
Which variable did Hector change on purpose in his investigation?