Stacy is vigilant in watching her baby for any change in her breathing. this is an example of attention.

a. executive
b. selective
c. divided
d. sustained

This is an example of SUSTAINED ATTENTION.

Explanation: Sustained attention can be defined as the quality of being able to focus on a action or stimulus over a long period of time irresponsible of other distractions and disturbing actions happening around. This is a Cognitive skill and it helps us to perform well in our daily activities to carry out task that take a long period of time to complete.

Watching over the breath of her baby for change is Sustained attention as this kind of activity takes a very long period.

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