The answer is B as isotopes are different versions of the same chemical element containing the same amount of protons and electrons but different amounts of neutrons.
<span>El Niño during the time of 1997 to 1998 caused drought in Southeast Asia and flooding in much of Latin America and in the Horn of Africa due to significant amounts of rainfall. The effects in both places were numerous deaths. In areas where it flooded, mudslides occurred and spoiled seed stores. In areas of drought, crops were extremely diminished and let to starvation.</span>
C. 50%
Unless the question is saying he only gets heads once, in which case it would be 0%. Or the coin could have 2 heads. Then it would be 100%.
But I'm pretty sure it's 50%.
-<u><em>Oxygen</em></u>
According to Google these are the percentages of the <em>Earths Atmosphere</em>
<em>1</em> 78% - Nitrogen
<u>2</u> 21% - Oxygen
<em>3</em> 0.9% - Argon
<em>4 </em>0.3 - Carbon Dioxide with very small percentage of other elements.