People under 40 usually use their thumb when using phone whereas older people use their index finger. Their texting styles are different. Young people use more emoji and older people use '^^' or '~'. Some older people have small talking with strangers but young people rarely do. I think young people are more likely to be individualistic.

Hello, Seong Eun!

Thanks for writing your homework.
Those are really good observations, haha!

Have a great day! 

-T.Jhozel 

People under 40 usually use their thumb when using phone whereas older people use their index finger.

>> Correct!
OR: People under the age of 40 typically use their thumbs when using phones, whereas older people use their index fingers.

Their texting styles are different. Young people use more emoji and older people use '^^' or '~'.

>> Correct!
OR: Their texting styles vary. Emoji are more popular among younger people, while older people prefer '^' or '^'.

Some older people have small talking with strangers but young people rarely do. 

>> Correct!
OR: Some older people make small talk with strangers, but young people rarely do. 

I think young people are more likely to be individualistic.

>> Correct!
OR: Individualistic behavior, in my opinion, is more common among young people.