What is a control used for in an experiment?

The control is what you keep the same for each one. For example if you are doing an experiment with plants say you water one with lemon juice, one with milk and one with warm water. The control would be they all have the same amount of sun light and soil. So the growing is equal to keep the experiment fair.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

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

Where is the illustration?