Which of the following was a cause of the ecological disaster known as the dust bowl?

a. excessive rainfall that year
b. a flood in california
c. a massive earthquake that loosened the topsoil
d. the plowing under of native grasses that kept topsoil in place

Germany italy and japan formed the tripartite pact in part because they: a. hoped to convince the united states to stay out of world war ii b. share the ruling philosophies based on communist economics c. resented the agreements they were forced to sign at the munich conference d. believed their territories were threatened by aggressive foreign states