Answer:
Laser beams
Explanation:
The laser beams technology is being used by bar code reader.
OSHA requires that if you work in an environment in which you're at risk of being hit by something that falls, you must: Secure tools and materials to prevent them from falling on people below. Barricade hazard areas and post warning signs. Use toe boards, screens on guardrails or scaffolds to prevent falling objects.
Blind Carbon Copy
For emails. It is used to send a copy of the email to somebody without the original person receiving it knowing that you sent a copy.
You should use needle-nose pliers, or sometimes even specially designed wrenches to screw on broadheads.