Choose the statement that best explains how railroad companies were able to standardize their timetables in 1883.
a. by combining into a single railway company
b. by working together voluntarily
c. by unionizing their labor forces
d. by complying with federal legislation

What contributes to the high level of biodiversity found in wetlands? a. the large amount of available organic matter to organisms that are food for larger organisms b. the amount of available water for organism use c. the high nutrient availability d. all of the above select the best answer from the choices provided a b c d