Among the oil crops, sunflower (Helianthus annuus) is the one that presents the highest expansion rate in the world. According to the United States Department of Agriculture (USDA, 2015), the world ...

It's a win-win, and it's why everything on iStock is only available royalty-free — including all Abstract images and footage. What kinds of royalty-free files are available on iStock? How can you use ...