<span>It changed Americans' economic expectations.</span>
Jamestown experienced a drought from 1606 to 1612
You need to know the laws<span> of motion and gravity </span>discovered<span> by English physicist Isaac </span>Newton<span>, and the </span>laws<span> of orbital motion</span>discovered<span> by German astronomer Johannes Kepler. ... </span>Newton's law<span> of universal gravitation states that gravitational force decreases with distance and mass.</span>
Answer:
Most research uses both primary and secondary sources. They complement each other to help you build a convincing argument. Primary sources are more credible as evidence, but secondary sources show how your work relates to existing research.
