Answer:
I think it is D.Factories
Explanation
Around this time the economy in the US became very industrial because of the fall of agriculture since a lot of farmers moved north to work in factories
you forgot to add the answers....
<span>Which of these tools can be used by archeologists to find fossils?
</span><span>An aerial photograph
</span><span>Which of the following describes a function of a satellite?
</span><span>Helps scientists track weather
</span><span>Which of these can vary in length of time?
Era
</span><span>The following examples are primary sources except
</span><span>an encyclopedia that provides factual details about the finding of Lucy
</span><span>A historian wonders why an ancient civilization disappeared. He suggests that a natural disaster might have destroyed it thousands of years ago. What step should the historian take next?
</span><span>Test the hypothesis
</span>
<span>Advancements in navigation. The Gupta Empire were very advanced in the fields of technology, science and art. The scholar Aryabhatta calculated that a solar </span>year was 365.358, <span>he also calculated </span>pi<span> to the fourth decimal place at a </span>value of 3.1416. <span>Kings in the </span>Gupta empire<span> owned huge copper, gold, and iron mines, and made advancements in metalworking. </span>
