Theory:

Earth is a green planet which is filled with many plants and animal species. In the world, a lot of diversity exists within plants and animals. There are plenty of natural plant resources that are present around us.
 
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The earth
 
Economic botany is a field of science that focuses on how plants can be useful for people. It primarily deals with how plants are useful for human welfare - as food, clothing, shelter and medicine, which are used directly or indirectly.
 
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Diversity in living organisms
  
Indirect usage includes the needs of man's livestock and the maintenance of the environment. The direct benefits may be commercial, domestic, environmental, or also can be aesthetic.
Plants are useful for the country's economy to a great extent. It is also noted that a country's wealth depends mostly upon agriculture and plant products.
Economic botany is the study of the relationship between people and plants and the usefulness of plants in the economy.
Rice, wheat, and millets have been the staple foods of the Indian population seen in ancient times. Evidence includes the presence of charred grains in the excavation sites. In addition, abundant information is available in ancient literature about the existence and usage of several crops that are of economic importance.
Uses of plants to humans:
Plants provide oxygen (\(O_2\)) through the process of photosynthesis that is used for respiration by humans and other animals.
 
Plants are great contributors to the economy of a nation.
Economic plants can be utilised directly (in food) or indirectly (products that satisfy the need of humans' livestock and the maintenance of the environment) for humans' benefit.
Observe the pictures given below:
 
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Harvesting of paddy by farmers
  
Important!
Indians consume rice as food.
Women_at_work_in_a_small_scale_coir_spinning_unit_at_kollam.jpg
Women making rope using coir
  
Important!
The rope is made from fibres of plants, including hemp, jute or flax.
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Neem leaves
 
Important!
Neem leaves are used for medicinal purposes as well as for pesticides or insecticides.
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Using the wood (obtained from plants) to make wooden products
 
In this chapter, the different crop plants and their usefulness in the economy are discussed.
Reference:
https://commons.wikimedia.org/wiki/File:Elements-of-biodiversity.png
https://upload.wikimedia.org/wikipedia/commons/thumb/b/be/Women_at_work_in_a_small_scale_coir_spinning_unit_at_kollam.jpg/512px-Women_at_work_in_a_small_scale_coir_spinning_unit_at_kollam.jpg
https://upload.wikimedia.org/wikipedia/commons/f/f1/%281%29_Agriculture_and_rural_farms_of_India.jpg
https://www.flickr.com/photos/cifor/37158925023