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

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Explanation:

Noticed that saplings of the plant would still curve forward into light unless the tip of their ranges were available. The crop developed straight ahead as they cut the edge of such a grass crop, instead of just rotating forward towards the ground.The target stayed straightforward as they put an opaque caps over its end. However, when individuals positioned a transparent caps on its own edge, or perhaps an opaque mask over its core, it streamlined.This was found that perhaps the shoot's tip was essential to detect light. Acknowledged that although the answer to development, trying to bend the shooting, actually happens beneath the tip. A certain message was conveyed downwards from either the service charge to the take the shot's growing market.