Given the age of the meteorite is 4.5 billion years old with 78 atoms of lead-206 the answer should be B. 156. The half-life of uranium-238 in order to decay into lead-206 is 4.46 billion years, which means that the original number of atoms is 156.
<h3>To round to a significant figure:</h3>
- look at the first non-zero digit if rounding to one significant figure.
- look at the digit after the first non-zero digit if rounding to two significant figures.
- draw a vertical line after the place value digit that is required.
- look at the next digit.
Plants use and produce both oxygen and carbon dioxide.
It's the first one where it resist change in pH solutions by neutralizing :)
