Food is the most vital product of the agriculture sector. But there other non-food products critical to the economy generated in this multi-billion dollar industry, including cotton, wool and tobacco. Prior to the Great Depression, government subsidies to the agriculture sector were relatively limited.
Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, that all cells come from preexisting cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
Body Systems: Tissues. At this point students know that cells make up all living things. But cells do not work independently within complex organisms such as plants, animals and of course people. Cells work together in organisms like people in an organized way that allows that organism to survive. This page explains how complex organisms are organized or another way of looking at it would be to say how complex living things are built. All complex organisms are made of groups of cells called tissues. Histologists are scientists that are experts on tissues. Tissues are groups of cells working together to get a certain job done. There are four basic types of tissues that make up the body --->. Organs are a groups of different tissues working together to complete a life function. Organ systems are many organs, tissues and cells working together to complete a life function.