Students filled up five test tubes with milk, which contains lactose sugar. They added methylene blue, which is an oxygen indicator to each test tube. The students left one test tube without yeast. They put 2ml of yeast, 3ml yeast, 4ml of yeast and Sml of yeast in the next 4 test
tubes. They timed how long it took for the yeast to deplete the oxygen in each test tube.
What is the independent variable in this experiment?

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.

Where is the nictitating membrane found? a. between the eyelid and the eyeball b. between the retina and the optic nerve c. between the outer and middle ear d. in the organ of corti in the middle ear