In plants, a tropism refers to the growth of a plant in response to an external stimulus. Plants can grow either towards or away from stimuli. The curving of plants is frequently due to differential growth, where different sides of a stem or root grow at different rates.n plants, a tropism refers to the growth of a plant in response to an external stimulus. Plants can grow either towards or away from stimuli. The curving of plants is frequently due to differential growth, where different sides of a stem or root grow at different rates.
There is an exact numerical answer to this question. By definition, 1 light year is exactly 9,460,730,472,580,800 meters. By definition, 1 mile is exactly 1,609.344 meters. So, 1 light year is exactly 5,878,625,373,183 and 849/1397 miles, by definition. Written May 20 â¢ View Upvotes.
Thatâs very fast. If you could travel at the speed of light, you would be able to circle the Earthâs equator about 7.5 times in just one second! A light-second is the distance light travels in one second, or 7.5 times the distance around Earthâs equator. A light-year is the distance light travels in one year. How far is that? Multiply the number of seconds in one year by the number of miles or kilometers that light travels in one second, and there you have it: one light-year.