Which best explains why some radioisotopes decay in a decay series ?

The forces that normally hold the nucleus together sometimes can't do the job, and so the nucleus breaks apart, undergoing nuclear decay. All elements with 84 or more protons are unstable; they eventually undergo decay. Other isotopes with fewer protons in their nucleus are also radioactive

Ans. : frostbite is when exposure to cold temperatures causes freezing to the skin or other tissues. it most commonly affects the hands, feet, and face. the longer areas are exposed to cold, typically the worse the frostbite. the water temperature used for rewarming a frostbitten part should be : (102 -105) f degrees.

Answer:   d.  carbon dioxide.