Question

what are artefacts? how do they help reconstruct the past

Answer 1

Archaeology is primarily concerned with reconstructing extinct cultures from the material remains of past human behavior, or the things people made or used and left behind. These remains are called artifacts. Much of what we see around us – computers, clothing, food, books, and buildings – are artifacts.

Answer 2

Factorize 21a^2-57ab+40b^2