Final answer:
In mathematics, symbols or variables can be used to represent unknown or changing quantities. In the given context, a constant can change to '*' and '#' can change to a constant.
Step-by-step explanation:
In mathematics, we often use symbols or variables to represent unknown or changing quantities. In the given question, the '#' symbol is being used to represent a variable or an unknown quantity, while the '*' symbol is being used to represent a constant quantity.
So, in the context of the question, the correct statement would be: A constant can change to '*' and '#' can change to a constant.
For example, if we let a = 5, then the equation 2 * a would mean 2 times the value of the constant 'a', which is 10.