When doing research for your Tissues and Systems Study project, the following links might be helpful:
http://www.eresources.knowledgeontario.ca
Lets you search full text scientific journal articles. These are written and reviewed by scientists, so they are very reliable sources. It also has a database to search specifically Canadian content from Canadian magazines, newspapers, and other sources.
If you are having difficulty finding what you need in your research, this website allows you to communicate online with librarians who are very knowledgable to help you out.
Look here if you are trying to find out information on your topic that relates specifically to Ontario.
Other websites you might be able to use:
Periodic table www.ptable.com and www.webelements.com