A is yours answer I think
16 neutrons are present in the most abundant isotope.
Explanation:
Phosphorus has 18 isotopes. The most common isotope has mass number (no. of protons 15+ no. of neutrons 16=) 31 .
It can be observed and tested
Lithosphere is the final layer on the planet Earth, erosion caused by wind (atmosphere) or rain (hydrosphere) may also wear down rocks in the lithosphere.
A heart beat, breathing, and moving ;)
