Which of the following statements about transportation costs is true? A. Transportation costs have little effect on the costs of production in agriculture. Transportation costs affect the availability of arable land. C. Transportation costs are an important factor in agricultural profitability. D. Transportation costs have increased in recent decades.​

C i think lol

Explanation:

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

1. artillery

2. jose san martin

3.their economies remained dependent on outside powers.

4. drafted new economies

5. democracies have replaced dictatorships