Final Answer:
The graph of the parabola \( x = y^2 \) is a function \( X \rightarrow Y \) only when \( e. \) \( y \) is non-negative.
Step-by-step explanation:
To determine if the graph of the parabola \( x = y^2 \) represents a function, we need to examine the vertical line test. For a relation to be a function, each \( x \) value should correspond to a unique \( y \) value.
In the given equation \( x = y^2 \), every \( x \) value corresponds to two \( y \) values: one positive and one negative since \( y = \pm \sqrt{x} \). Therefore, to satisfy the criteria of a function, we consider only the non-negative values of \( y \).
Selecting option \( e. \) "y is non-negative" is the correct choice. This means that for each \( x \) value, there is only one non-negative \( y \) value, adhering to the definition of a function.
In summary, the graph of the parabola \( x = y^2 \) represents a function when \( y \) is non-negative. This ensures that each \( x \) value has a unique corresponding \( y \) value, fulfilling the criteria for a function.
The other options either include both positive and negative \( y \) values (violating the vertical line test) or impose additional conditions that do not guarantee a one-to-one correspondence between \( x \) and \( y \).