Answer:
Since different isotopes of an element have different numbers of neutrons (but always the same number of protons) they have different mass numbers. Nitrogen-14 and nitrogen-15 are both stable isotopes of nitrogen. However, the other 5 isotopes are all unstable.
Answer:
The spinning motion of Earth on its axis is called a rotation. Day refers to the amount of time it takes a planet to rotate one complete time.
Explanation:
Star-forming<span> regions are a class of emission </span>nebula <span>associated with giant molecular clouds. These form as a molecular cloud collapses under its own weight, proceeding stars. Massive stars may form in the center, and their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths.</span><span>
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Hopes this helps.</span>
Answer:
Weather includes such conditions as air pressure, wind, <em><u>temp</u></em><em><u>erature</u></em><em><u> </u></em>, and moisture in the air.