The last period of the text is in the present perfect tense...

Text for items from 23 to 25.

What is agronomy? An agronomist, or crop scientist, studies plants and how they can be grown, modified, and used to benefit society. They use science to carry out experiments that create new techniques for agriculture production. Agronomy has existed and been important for humans since the invention of farming.

Internet: <unity.edu> (with adaptations).

According to the text, judge the items from 23 to 25.