cells with the same function together will form a tissue. A tissue is a
group of cells that carry out the same function. A tissue can be
composed of several types of cells, but they all perform the same job.
Example: skin tissue. It is usually a layer of cells, if that helps you
Then, several types of tissue will be organized in an organ. Examples
are liver, kidney, stomach. These organs consists of many different
types of tissues. An organ is usually much bigger than one layer, it is a
visible thing, if that helps you understand it better.
Finally, an organ system is a group of organs that are doing a similar
function. A good example is the digestive system. Here, the mouth,
stomach, small intestine, large intestine, liver, and gall bladder form one big group of organs that will help you digest
Hope that was helpful.