In the late 1870s,Charles Darwin and his son Francis discovered that if the tip of the grass was covered,phototropism did not occur,even though the rest of the grass was exposed to light.However,if the rest of the plant was covered and only the tip exposed to light,the grass bent a few centimeters below the tip.How could light striking the tip of the grass cause bending a few centimeters from the tip? Choose the most likely explanation from the below choices.

Question

Quizplus · Accepted Answer

The most likely explanation is that a hormone, produced at the tip of the grass when exposed to light, is transported down to the cells a few centimeters below the tip, causing them to elongate and the grass to bend. This process is known as phototropism, where plants grow towards a light source, and it is mediated by the distribution of plant hormones like auxin.

In the Late 1870s,Charles Darwin and His Son Francis Discovered