The answer would be abstract art.
The question is incomplete and the full version can be found online.
Answer: Art Theory
Explanation:
Leon Battista Alberti, (1404 - 1472) was an Italian architect whose treatises De Pictura (1535), De Re Aedificatoria (ca. 1450), and De Statua (ca. 1462) contributed to the development of art theory about painting, architecture, and sculpture, and established him as the father of Renaissance art theory.
Alberti´s work was considered a key element of the Florentine Renaissance, as it presented the rules of scientific and mathematical balance of a new art theory.
They are important because without them there is basically no drawing every drawing includes lines
