Plants and humans have developed a mutual plan for survival. Plants provide humans with oxygen through photosynthesis, food, clothing and shelter. In return, humans expel carbon dioxide and disperse plant seeds throughout the world.

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Oxygen

The mutual arrangement plants have with humans is through photosynthesis. The process of photosynthesis combines sunlight with carbon dioxide and water -- which produces food for the plant and oxygen for humans.

Food

Plants provide food for humans by growing fruits, vegetables and grains. Plants also provide nutrients to livestock which many humans eat.

Clothing and More

Cotton, hemp and flax are plant materials used to make clothing. These plants offer a variety of uses once fibers are cultivated -- such as clothing, paper, rope, oil and numerous other items.

Shelter

Plants provide material for shelter. This includes planks of wood from trees, straw for roofs and bricks, and leaves that can be used for roof materials and shelters. Early bricks were made by combining straw, water and clay. Mixing these ingredients together, placing in molds and drying in the sun or oven are the basic steps required to make a simple brick.

Herbs

Herbs enhance the human diet by adding flavor, color and aroma to what you eat. Herbs also create cultural identities that you can associate with certain meals. Middle Eastern cuisine, for example, is associated with turmeric -- while Italian dishes are identified with garlic and basil.

Medicine

Many medicines are created from plants. Birch leaves or willow bark were once used to relieve pain. Stronger pain relievers such as opium, were harvested from poppy plants. Herbs have also played a role in preventative medicine. Garlic is added to honey to enhance the immune system, while sage is used to help fight the common cold.