Explain why alchemy is not as reliable as modern day science

Explanation:

Alchemy is the forerunner of modern chemistry practiced during the medieval times. Chemists of those times were known and called alchemists.

These chemists had a very shallow knowledge of chemistry but were able to produce a wide range of chemicals.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).