Federal reserve banks directly affect the national economy by

administering consumer protection laws
increasing and decreasing the money supply
providing oversight and services for financial institutions
raising and lowering interest rates

increasing and decreasing the money supply  

raising and lowering interest rates

Explanation:

The Federal Reserve is the body responsible for conducting the government's monetary policy. Monetary policy consists of raising / lowering the interest rate and increasing / decreasing the amount of currency in circulation in the economy through the purchase or sale of government securities. Thus, the Federal Reserve acts to keep inflation under control and the economic environment healthy and prone to economic transactions.

d) the number of neutrons plus the number of protons

the answer is mosques. they are an important part of islamic culture.