Answer:
a. 0.5 grams b. 0.25
Explanation:
Just use the half-life formula(I linked it below)
a. 4(1/2)^90/30=1/2
b. 4(1/2)^120/30=1/4
Which is not an emotional reaction to stress?
picking a fight
feeling moody or aggressive
noticing your heart racing
bursting into tears more often
Hydrogen, oxygen, and nitrogen atoms.