<script async="async" data-cfasync="false" src="//pl26957908.profitableratecpm.com/d35f33434b3aa9b2ca989e6d82c46375/invoke.js"></script> <div id="container-d35f33434b3aa9b2ca989e6d82c46375"></div>         Cell Theory 

 All animals and plants are constituted of certain structural units,which are repeted in each animal or plant.Such a concept was originally put forward by Aristotle(384-322 B.C.).Many centuries later,for these units, a term "cell" was used by Robert Hooke, who in 1665,observed these so called cells for the first time in a piece of cork under a very primitive microscope.Later ,cells in the form of cavaties with cellulose walls were observed in different plants by Grew and Malpighi,in 1674.Leeuwenhoek also discovered free cells and observed some organization within these cells.<script async="async" data-cfasync="false" src="//pl26957908.profitableratecpm.com/d35f33434b3aa9b2ca989e6d82c46375/invoke.js"></script>

<div id="container-d35f33434b3aa9b2ca989e6d82c46375"></div>