Which continent falls in all four hemispheres

Africa because the prime meridian¹ "splits" part of Africa from from the western and eastern hemisphere, while the equator² also "splits" the landmass from the northern and southern hemisphere.

¹the straight imaginary line that comes from the north pole down through London to the south pole (0 degrees longitude).

²The imaginary line that splits the north and south hemispheres. (0 degrees latitude.