Which two of these items were requirements that the Berlin Conference imposed on European nations claiming colonies in Africa?

notifying other European nations when taking possession of African territories

and

actively occupying the territory, as shown by a flag and keeping a police force

Explanation:

Patent law in the US is the Patent Act. It protects new inventions and establishes the US Patent Office to accept patent applications. Its authority is from the US Constitution which says "Congress shall have power to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries."