The principle that serves as a foundation for personal injury law is that everyone has a certain degree of duty to care for others. This care is to be executed in the form of taking reasonable measures to protect others from unnecessary harm or injury. The standard of care required from each person will differ depending on the situation and nature of relation between the alleged defendant and the plaintiff but the failure to exercise reasonable care is generally referred to as negligence. Negligence, in personal injury, is conduct, behavior, action or inaction that falls below the standard of care expected from a certain party to protect others from unreasonable risk of harm.