Subsoil: This layer has normally less organic matter than the A horizon, so its colour is mainly derived from iron oxides. Iron oxides and clay minerals accumulate as a result of weathering. In a soil, where substances move down from the topsoil, this is the layer, where they accumulate.
Note: This information has been taken out of a website.
The answer is B. The lines of Latitude are about 69 miles apart. Each line of latitude is 1 degree of the angle of circumference of the earth, with parallel latitude lines lined up going East-West. Since the lines are stacked up north to south, your latitude describes your North/South position on the earth. Since these lines are parallel, their distance in generally constant.
The country that is an isthmus and links central and Souh America is Panama