The force of gravity also causes the planets to be in their orbits. This is a good interactive site for students of science to learn more about gravity. This site comes complete with everything that has to be understood about atoms. It includes the history of the atomic theory right to its present state, it has an interactive periodic table which will be of great help to all students of chemistry. This site discusses the reproduction, structure of these two different kinds of plants very clearly.
Plants too have hormones.
This site will enable the plant physiology student to learn more about the types of plant hormones and their functions. It has simple slides to revise some important chemistry concepts. There are also exercises and homework that will help to reinforce understanding. Another Site Mitotic stages are usually seen in digramatic form. This site has excellent microphotographs of the actual stages in plant and animal cells.