Many of the advances of civilisation have been conceived by young people just on the …… of adulthood A. boundary B. threshold C. peak D. horizon

The correct answer is threshold.

A threshold is a point at which something changes or begins. In this case, it refers to the point at which young people become adults. Many of the advances of civilization have been conceived by young people just on the threshold of adulthood, because they are at a time in their lives when they are full of energy, creativity, and ambition. They are also not afraid to take risks and challenge the status quo.

The other options are not as accurate. A boundary is a line that separates two things. A peak is the highest point of something. A horizon is the line that separates the sky from the land or sea.