For which of the following mineral resources is the United States most dependent on imports?

For which of the following mineral resources is the United States most dependent on imports?
  a. nickel
  b. copper
  c. chromium
  d. graphite
  e. tin

Which important agricultural substance comes from the atmosphere?
  a. nitrate
  b. phosphate
  c. potassium
  d. potash
  e. calcium

For which of the following non-metallic mineral resources dose the United States produce more than it
  consumes?
  a. clay
  b. gypsum
  c. potash
  d. salt
  e. sulfur

Judge the following sentence according to the criteria given below: Aluminum is concentrated in the
  formation of bauxite ore BECAUSE it is relatively insoluble during the deep chemical weathering that
  occurs in hot, humid tropical climates.
  a. The assertion and reason are both correct, and the reason is valid.
  b. The assertion and reason are both correct, and the reason is invalid.
  c. The assertion is correct and the reason is incorrect.
  d. The assertion is incorrect and the reason is correct.
  e. Both the assertion and the reason are incorrect

Most of the world's aluminum comes from which of the following?
  a. quartz
  b. bauxite
  c. hematite
  d. plagioclase
  e. basalt

What kind of process produces manganese nodules?
  a. physical sedimentation
  b. hydrothermal
  c. volcanogenic
  d. weathering
  e. chemical sedimentation

Which type of ore deposit originated before there was free oxygen in the atmosphere?
  a. banded iron formation
  b. manganese nodules
  c. colcanogenic copper
  d. gold placer deposits
  e. bauxite