Petra dropped her beaker on the floor. She placed her gloves on the table. She then started to pick up the small pieces with her hand and place them in the broken-glass container. At the end of lab, she told her instructor that there was broken glass on the floor. The teacher swept it up and placed the glass in the broken-glass container. Aside from dropping the beaker, how many errors did Petra commit?

one
two
three
four