A student attempts to focus a gram-stained slide under the 40x lens but it is not successful. Which of the following suggestions might help the student focus his slide?
1)sk one of the lab TAs for help
2) Go back to the 10X lens and make sure the slide is in focus under that objective
3) Try finding a wax pencil mark on the slide and focusing on that first
4) All of the above are good suggestions