Which statement about the number of 25- to 45-year-olds living alone is correct? It has remained relatively constant since the 1990s.
It has increased slightly since the 1990s.
It has doubled over the past twenty years.
It has quadrupled over the last twenty years.

Which statement best describes common communicable diseases? a. most communicable diseases are either bacterial or viral and infect the respiratory tract. b. all communicable diseases are viruses that cause pneumonia. c. most communicable disease are bacteria and viruses that infect the intestinal tract. d. all communicable diseases are bacteria that grow in the respiratory tract. select the best answer from the choices provided. a b c d