Joanna read that certain perfumes would cause bees to leave the hive and act in an agitated fashion. She decided to investigate the response of bees to five different perfumes- Ralph Lauren, Armani, Mark Jacobs, Vera Wang, and the last is an odorless liquid. She placed a saucer containing 20ml of perfume A 10 meters from a beehive. She then recorded the total number of bees that emerged from the hive during a 15 minute interval and made observations on their behavior. Using a 30 minute interval between tests to allow recovery time for the bees, she then repeated the procedure to test the remaining three samples. Each test was conducted on the same day with similar weather conditions. whats the independent variable