Is this a complex or simple sentence?
I saw the new hat that she had bought.

Simple sentence

Explanation:

There is no conjunction (such as; and, but, or, etc).

answer: this is not a good thesis statement because a thesis statement is not supposed to have questions in it. a thesis states your position on your topic. a question cannot state anything because it is not a statement. a question is a great lead in to a thesis, but it can't be the thesis.

i think the life is invaluable.

you can also say immeasurable.