31) How did U. S. participation in World War I contribute to its emergence as a world power in the early 20th century?

Select all the correct answers.

A) The U. S. enjoyed a period of economic prosperity after the war.
B) The U. S. mobilized a large army and navy to help the Allies achieve victory.
C) The U. S. weakened the Allied countries by making France, England and Russia reduce the size of their
armies.
D) The U. S. mobilized a large army and navy to help the Allies achieve victory.

Astudy was performed on 20 trees to test the effectiveness of a new fertilizer. the results of this specific study is brought into question. what would possibly improve the reliability of the results?

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.

Archeologists have discovered three sites showing conclusive evidence for the mastery of fire in tanzania, from a period slightly after the time that homo habilis was present in africa. these sites clearly were founded by homo erectus, the descendent species of homo habilis that migrated north, out of africa and into asia. homo erectus was known to have mastered fire, from ample evidence at sites in asia. there is no reason to attribute mastery of fire to homo ergaster, the descendent species of homo habilis that remained in africa.which of the following is an assumption on which the argument depends? (a) before their migration, homo erectus occupied african territory as far south as tanzania.(b) the strain of migration provided the selective pressure motivating homo erectus‘ mastery of fire.(c) homo ergaster would not have derived as much benefit from the mastery of fire as did homo erectus.(d) homo ergaster inherited all cultural knowledge from homo habilis, a species that did not have mastery of fire.(e) homo ergaster did not occupy regions as far south as tanzania until well after the time of these three sites.