Q.What is an "expanding" age pyramid, and what shape does it show?

An expanding population has a large proportion of pre-reproductive individuals relative to reproductive and post-reproductive individuals. When plotted as an age pyramid — a stacked bar graph running from the youngest age class at the bottom to the oldest at the top — this produces a broad base tapering sharply to a narrow apex, giving the pyramid a roughly triangular shape. Because so many individuals have not yet entered their reproductive years, this population …

Link the shape word ("triangular"/"broad base") directly to the reason ("many pre-reproductive individuals still to reproduc …

Do not confuse the expanding (triangular) pyramid with the declining (urn-shaped, narrow base) pyra …