15. Complete the following with the terms “new element". ion, isotope, or molecule. Add another atom
Add or subtract a neutron
Atom
Add or subtract a proton
Add or subtract an electron

explanation:

i think option no d is the correct answer

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.