Answer: B for 1st question and D for 2nd question
Explanation: I'm pretty sure this is right and I hope this helps.
One of the main reasons why primary sources are valuable to historians is because "<span>They give insight into the thoughts and feelings of a participant in history," since these are sources that originated during the time in question, and are "unaltered". </span>
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Economists refer to the polarization of the labor force when middle-class jobs requiring a moderate level of skills, like autoworkers' jobs seem to disappear relative to those at the bottom, requiring few skills, and those at the top, requiring greater skill levels.
<h3>What causes a polarized society?</h3>
Social polarization is the segregation within a society that emerges when factors such as income inequality, real-estate fluctuations, and economic displacement result in the differentiation of social groups from high-income to low-income.
<h3>
What is the polarization effect?</h3>
Polarization refers to an effect reducing the performance of batteries. This effect is a displacement of electrode potential from the equilibrium value. There are two types of polarization: activation and concentration.
Learn more about polarization here: brainly.com/question/13090534
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Answer:
Inventions like the airplane and machine gun
Explanation:
World War I was so deadly because all of the new weapons that were invented. New technology that was being invented such as machine guns and mustard gas made war deadlier than every war before.
