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

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Number and variety of living organisms includes genetic, species, and ecological types

Plz ! what does it mean for an allele to be dominant?