Question

Through the 20th century and continuing today, the nature of federalism has changed over time with new demands that have tended toward a system where the state and national governments share many responsibilities. This is called

a Separation of power B cooperative federalism C distribution of wealth d socialism

Answer 1

I'm sorry but what exactly are asking?

Answer 2

For the answer to the question above, that is called "cooperative federalism" since the more that a federal (central) power works with state powers, the more the country can move forward.
I hope my answer helped you. Have a nice day!