Why should the president of the united states visit schools. explain.

Explanation:To show them why it is important to go to school because you can be become a United States precedent.

The eye symbol represents eye and face hazard.

Explanation:

The eye symbol represents the presence of chemicals or radiations at working place which can affect your eyesight and facial tissues. So, the symbol meant to use black goggles and face mask to protect eyes and facial tissues.

Hazards which means danger or problems occurring in work place or area due to chemicals. The chemicals and radiations can cause various hazards if proper protection were not taken.

So, all laboratories performing operations with these kinds of hazardous radiations must have symbols representing the kinds of hazards.