If Gallium-68 has a half-life of 68.3 minutes, how much of a 115 mg sample is left after 6 half-lives?
5 mg
1.8 mg
0.6 mg
none of the above

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.

Radioactive fallout is a result of the fission creation used to ignite the thermonuclear fusion reaction.

Is there a c and d?

"form only at boundaries  between two continental plates." this is the correct answer.