Hello good afternoon...God bless the answer to your following question is D
because...A crest point on a wave is the maximum value of upward displacement within a cycle. A crest is a point on a surface wave where the displacement of the medium is at a maximum. A trough is the opposite of a crest, so the minimum or lowest point in a cycle.
Each element is made up of only one kind of atom.
When concentrated sulfuric acid, H2SO4(l), is added to water it will form a solution containing hydrogen ions and hydrogen sulfate ions. H2SO4 is a strong acid, but only for the first H+. The remaining HSO4^- is a weak acid. Since it forms an acidic solution, it will change blue litmus to red.
Answer:
288 grams
Explanation:
The amount of any radiative substance left after some time is calculated by
amount left = 
where x is the initial amount of substance
n is the number of half lives
one half live is the time in which amount of substance reduce to half of its initial value.
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amount left = 4.5 grams
half life of iodine-125 = 60 days
total time in which substance reduced to 4.5 grams = 360 days
thus,
number of half life in 60 days = 360/60 = 6
thus, there are period of 6 half lives
in each half life the amount of substance reduces to its previous half
let the initial amount be x grams
using the formula
amount left = 

Thus, 288 grams was the initial amount of iodine-125