Well first off every thing will be more expensive because we will have more money since we are not using it to buy food any more. we would get more money, save more money, and every thing will cost a lot more. Many people will lose jobs because they won't be making food any more (like people at mcdonalds) and then to get a job people will need higher intellect. The population of cows, pigs, and other animals that we eat will rise and they won't be domesticated any more (unless you want to keep a pet chicken, thats fine with me) and the evolution line might change. Then the downside is that the people live in a climate where it is mostly cloudy and dark will be more hungry and will probably move to warmer areas where they can get enough food. People in warmer climate can just sit outside for a few hours and they will be full and not hungry. As you can see if people began to use photosynthesis to get food. many things will change.
I hope this helped. :3
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Because a caterpillar is a heterotroph and it cannot make its own food so it relies on the energy in plant sugars and by eating plants it gets energy from the sun in an indirect way. So to put it simply, the caterpillar uses light captured energy for energy.
Scientists use the light year because nothing can travel fast than light. Therefore, in any given time frame, light will travel farther than any other substance or particle in the universe. For more precise measurements, scientists use astronomical units. One AU is equal to the distance between the earth and the sun. For anything less, scientists usually use kilometers. For extremely large, interstellar distances, light years are very useful. You wouldn’t want to measure the distance between Earth and Proxima Centauri in kilometers or even AU. The lightyear gives a simple, relative measurement.
Ok since you don't have any answers to choose from I would say Functions is the right answer. Usually we're supposed to explain why but I'm not sure how to for this question, sorry.