Calcium loss was __________ times greater in deforested plots than in undisturbed areas in the ...

Calcium loss was __________ times greater in
  deforested plots than in undisturbed areas in the
  Hubbard Brook watershed experiment.
  a. three to six
  b. four to eight
  c. five to seven
  d. six to ten
  e. seven to twelve

Question 2

The Hubbard Brook watershed studies revealed the
  importance of tree roots in preventing loss of calcium
  from an ecosystem. Calculation of calcium loss is
  performed by sampling
  a. the roots of the trees in the watershed.
  b. the soil of the watershed.
  c. water exiting the watershed.
  d. lakes in the watershed.
  e. water in streams in the watershed