What is a effective thesis?

a thesis statement states the specific part of a topic you will write about. It also shows what about the topic you intend to prove.

A thesis statement has four functions:

• It limits your subject to a single topic (idea).
• It asserts something specific and significant about the topic.
• It conveys (or at least implies) your purpose in writing.
• It usually names the subdivisions of the topic in the order in which you will discuss them.