You are given a sentence and your task is to generate another sentence that supports the given input.

When the parallel rays of a light source strike a convex lens the rays will concentrate or focus at a specific point, the focal point .
Convex lenses are thicker in the middle than at the edges so they cause rays of light to converge, or meet, at a point called focus.

As are all vascular plants, the dominant generation for the seed plants is the sporophyte generation.
Vascular plants have a dominant sporophyte generation.

The light travel time for the most distant visible galaxies is several billion years, comparable to the age of the universe, so by studying distant galaxies we are also looking back in time.

Due to the time it takes for light to reach us, galaxies at the edge of the universe are distant in terms of space and time.