Over 315,000 plant species have been discovered. Plants are green because of chlorophyll and the means of photosynthesis. Majority of plants are autotrophs and make their food from the sun. These organisms take sunlight and carbon dioxide where it converts it into sugar which is used as food. Vacuoles in the plant's cells can store this food and use it later. Plants are stationary but they are a living organism. Different types of plantae include trees, flowers, grasses, bushes, moss, algae, ferns, vines, and herbs. To be successful, plants require certain amounts of water, carbon dioxcide, and sunlight. Different types of plantae need more water than others. Example: a cactus and a algae. The cactus requires less water and more sun, while the algae requires more water, and less sunshine. Plants are used quite often as nutrition to humans. Not only are they used as food, but trees can be used to make wood, which in turn can build houses, give us paper to write on, and a number of other tools essential for humans today. Negative effects from plants can include disease, weeds (which can be unpleasant in a garden), and some plants are used to make drugs.