When Hitler continued his aggression, Chamberlain pledged Britain to defend Poland's independence if the latter were attacked, an alliance that brought Britain into war when Germany attacked Poland in 1939.
FIND OUT MORE. The Earth is covered in a layer of solid rock called the crust. Rocks are either SEDIMENTARY, IGNEOUS, or METAMORPHIC. Almost all rocks made of minerals, but different rocks contain different mixtures of minerals.Granite, for example, consists of quartz, feldspar, and mica.IND OUT MORE. The Earth is covered in a layer of solid rock called the crust. Rocks are either SEDIMENTARY, IGNEOUS, or METAMORPHIC. Almost all rocks made of minerals, but different rocks contain different mixtures of minerals.
The layer of the Earth between the crust and the core. It is about 2,900 km (1,798 mi) thick and consists mainly of magnesium-iron silicate minerals, such as olivine and pyroxene. It has an upper, partially molten part, which is about 660 km (409 mi) thick, and a lower, solid part.