What is the most important action for all students to take to stay safe in a science lab? follow all instructions that are given by the teacher. do not talk with students sitting nearby. know where all laboratory equipment is located. have 911 programmed into one cell phone per table.

I would say A. Mainly because the teacher is well trained for situation where it's critical or something like that.. 

I would think it is to follow all instructions given by the teacher. if all instructions are followed than there should be no need to have 911 programmed into a cell phone. and whether the students talk or not is determined by the teacher. furthermore, the teacher should be the one to show students were the laboratory equipment are.