Word classes help

Hello! I need some help to define some word classes.

The words are:

Remarkable
Finding
Significant
During
Which
Registered
Control
Available
Most
Searches
Engages
Demonstrated
Plastic
You
Can
Tool
Especially
On
Mostly

They're taking from this text, if you want the full context:

A remarkable finding was that though all participants showed significant brain activity during book-reading tasks, which correspond to language, reading, memory and visual abilities, the web-savvy group also registered activity in the areas of the brain which control decision-making and complex reasoning. With the wealth of choices available on the net, knowing how to perform the most effective searches and making decisions on what to click on, engages important cognitive circuits in the brain. This finding also demonstrated that our brains are sensitive, or, “plastic”, and can continue to learn as we grow older.
So spending time on the Internet can be beneficial as you get older, but what about when you’re young? According to researchers from Michigan State University, home Internet access can be a good educational tool, especially for hard-to-reach populations. Also, it has had positive effects on the academic performance of low-income, mostly African American children and teenagers.