Does solar energy ever run out? brainliest

Ronald wants to see if a new shower cleaner works better in removing soap than his old cleaner. he uses the new cleaner on one half of the shower tiles and his old cleaner on the other half. identify the independent and dependent variables in this experiment. enter your answer in the space provided.

Which type of respiration takes place when there is no oxygen present? a. anaerobic b. mitochondrial c. cellular d. aerobica. anaerobic

Crossing over is a method of (blank)?