Explanation:
1) Initial mass of the Cesium-137=
= 180 mg
Mass of Cesium after time t = N
Formula used :
Half life of the cesium-137 =
= initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= rate constant

Now put all the given values in this formula, we get
Mass that remains after t years.

Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years


N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3)


N = 1 mg
t = ?

t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
Your answer is yeast, since it is a single celled organism that can be classified into a subkingdom related to sac fungi.
ELETRICK probably wondering why metal shocks (psst why does wires charge phones)
It is called rust and it forms when water soaks into the metal forming a chemical reaction.
Blood cells, glucose , skin cells and etc .