Cells in the human eye send nerve impulses to the brain that cause the pupil to constrict. This is an example of a reaction to what kind of stimuli?.

Writing it down so you can remember it but if you truly think nothing is to bad

Answer up to 6,000 fatal crashes a year;

Answerbipolar disorder; i believe this is correct, plz check first;

Immunization is the introduction of a foreign substance to provoke  the immune response system.  immunizations are the same as vaccinations. it introduces foreign (but dead/ weakened) illnesses to train the body to fight against them. specific viruses and bacteria have specific antigens, antigens act sort of like name tags. these name tags the immune system recognize what's dangerous to the body and what's safe.