In order to design an experiment, you need a about the scientific question you are trying to answer. a. decision b. procedure c. hypothesis d. conclusion

The correct answer is option C, that is, hypothesis.  

The hypothesis is the starting building block in the scientific method. It is also illustrated as an educated guess, based on previous observation and knowledge. A hypothesis refers to a recommended solution for an unexplained event, which does not fit into the present accepted scientific theory.  

The fundamental concept of a hypothesis is that there is no pre-determined result. For a hypothesis to be considered as scientific hypothesis, it has to be something, which can be refuted or supported via carefully crafted observation or experimentation.  

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer