Agricultural chemistry focuses on chemical compositions and changes involved in the production, protection, and use of crops and livestock. It seeks to control and understand the processes by which humans obtain food and fiber for them-selves and feed for their animals. Agricultural chemists work with food producers to increase yields, improve quality, and reduce costs. They also study the causes and effects of bio-chemical reactions related to plant and animal growth, seek ways to control these reactions, and develop chemical products that provide help in controlling these reactions. Chemical products developed to assist in the production of food, feed, and fiber include herbicides, fungicides, insecticides, plant growth regulators, fertilizers, and animal feed supplements.