A pigeon in operant chamber #1 regularly receives a pellet of food after every ten pecks at a red disk, no matter how long it takes. A rat in operant chamber #2 regularly receives a pellet of food for the first bar press it makes after ten minutes have passed, no matter how many bar presses it makes. The pigeon is on a schedule of reinforcement, and the rat is on a schedule of reinforcement.

A)fixed-ratio; fixed-interval
B)fixed-interval; fixed-ratio
C)fixed-ratio; variable-interval
D)fixed-ratio; variable-ratio

first, the romans stayed isolated because they had to defend their own territories from neighboring cities that were harassing them, like the etruscans. second, once the romans managed to defeat their neighbors, and started to expand their territory, they started to build roads and bridges. finally, now that the romans have covered their territory with roads functioning as highways, they could mobilize their legions faster to assemble larger military units in a specific place.

money is the anwser i think

answer; a biased sample;