B. The reason the temperature experienced no change in group c is because it was likely the control group.
I cannot read question c, the monitor refresh is obscuring the text.
Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at
, 


Answer:
Water/H20 is a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.
Explanation:
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The reaction in which more reactive element replace a less reactive element from its compound is called displacement reaction.
Ex:-

Lead is heavier and more resistant. Plastic foam is light and can easily be broken