How will the United States effectively navigate the problems of the 21st century and still live up to our ideals of freedom, equality, and democracy?

Well you have the answer for this question right

The correct answer is "true".

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.