Questions

bullet proof material is made up of polymer Poly carbonates.

Cretinism is a disease caused by hypothyroidism(less thyroxine formation).The symptoms of the disease are retardation  of mental, physical and sexual developments. Potbellt, protruding tongue, dry skin etc are also indicative of this disease.

Settled agriculture was first seen in China around 6000 BC. The crops grown at this time were rice and millet.

Beginning in about 618 BC with classical millet agriculture, China's development of farming over the course of its history has played a key role in supporting the growth of what is now the largest population in the world.

A magnetic domain is a region within a magnetic material in which the magnetization is in a uniform direction. This means that the individual magnetic moments of the atoms are aligned with one another and they point in the same direction.