Plants need very basic things to perform photosynthesis—light, water, carbon dioxide, and small amounts of other substances, such as phosphorus. What happens to a plant if one of these is not available? You might have noticed that when it doesn’t rain for a long time, the grass and other plants in people’s yards become yellow. That is because, without water, photosynthesis cannot take place.
The same thing is true of light. Without light, plants cannot perform photosynthesis, and their green color fades. If you have ever put a plant into a dark place, you might have observed this effect.
