Neutrons are located

a. in the nucleus with protons

b. in the nucleus with electrons

c. in orbit around the nucleus

d. both in orbit and in the nucleus

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.