<span>When you have to balance an equation it means that you have to balance both parts of equation so that the numbers of each elements will have the same amount. According to this rule, it is quite easy to distinguish unbalanced reaction, and the answer is a) HBr + Ca(OH)2 → CaBr2 + H2O as you can see that amount of oxygen on both sides is not the same.</span>
True. The prototype is usually the "rough draft" the figure out what needs fixed or upgraded before they make the final product "final draft". Hope that helped!
<span> Curium (Cm) is the answer.
Hope this helps.</span>