significant

(adj)large enough to be noticed or have an effect;very important.

There is a significant difference between prices in the stores.

The site is work in progress,but it's significant progress.

And here,there are dignificant quantiifiable racial disparities that cannot be ignored

The question is:Will you find something that is scientifically significant?

scientifically significant:from a scientific perspective enough to be noticed or have an effect.

It is a significant problem around the world.?

I decided I wanted to dedicate a signigicant amount of my life to solving climate change

? role

(n)a character played by an actor;a part that someone or something has in a particular activity or situation

I had a minor role in the play.

You played a role in my decision to move to New York.

I think everbody here recognizes the importance of a role model.

role model:a model person in taht role,an outstanding example

it also serves key roles in the cycles of life.

Our role as the foundation will be to help facilitate an environmental education program .

And also,importantly,what role does government have ?

major

(adj)very important a large number or amount;very serious

Researchers have announced a major advance in the treatment of cancer.

(n)the main subject studied by a college or university student.

He chose history as his major and French as his minor.

I started with math major in college with education minor.

and we've learned that there are major differeces in the ways that women and men experience disease.

The country lies along the delta of three major European rivers

This caused major delays in the development of the Falcon Heavy.

This is not the last major outbreak we're ever going to see.

period

(n)a length of time during which something happens.

the period between Christmas and New Year's Eve is a very busy.

(adj)about a particular time in history

The actors wore period costumes from the 1800s.

It's also a time period that I particularly love.

How long is the incubation period for COVID-19?

it was a veryscary period for all of us

a short period of time ,not enough to cover everthing they could have said