Is this a thesis statement? A nationwide ban on plastic bags is the best way to protect marine wildlife from litter.

Yes

Explanation:

A thesis statement is usually found at the end of the introduction to a body of writing that offers a summary.

Therefore, the statement: "A nationwide ban on plastic bags is the best way to protect marine wildlife from litter" is an example of a thesis statement.

for the word research, just look up in the dictionary or on an electronic the definition of research.

then just draw a simple picture of research

then for an antonym, your putting the opposite of the word research, which might be in the dictionary

and finally for the synonym, do a word that also means research, once again might be in the dictionary

hope this helped!