Define the exclusionary rule.

legal principle defining the concept of finding evidence in plain view.
legal principle defining how evidence can be legally collected.
legal principle defining what an arrest warrants prohibits.
legal principle defining probable cause for an arrest.

He issued the emancipation proclamation. it started changing slavery, and eventually lead to the freedom of slaves.

True blindness may be caused by trauma to the eye, severe conjunctivitis due to  ibr (infectious bovine rhinoceros) or pink eye or other infections, leptospirosis, lead poisoning, selenium toxicity, fungal infections, vitamin a  deficiencies, rabies, vitamin b12 deficiency, neoplastic of the orbit or  conjunctiva, cataracts, congenital malformations, etc.