What do parties do to select the party's presidential candidate? which members of the party are involved? when do they take these actions?

Read this quote from article i of the constitution. congress shall have power . . [t]o make all laws which shall be necessary and proper for carrying into execution the foregoing powers. which type of powers does this quote refer to, and why is this type often the source of debate? the quote refers to reserved powers, which are given to the states to interpret as they will. the quote refers to expressed powers, which are not considered either “necessary or proper.” the quote refers to concurrent powers, which are difficult to implement equally in every state. the quote refers to implied powers, which are often difficult to interpret or understand.