Plants Are Sometimes Used for Phytoremediation in Areas Where the Soil

Plants are sometimes used for phytoremediation in areas where the soil has been contaminated with heavy metals. Suppose the Acme Remediation Company is proposing to remediate a contaminated area that you wish to restore. Acme presents you with the following data as evidence of their company's ability to remediate soil.

-Which of the following is a question you should ask Acme about conclusions to be drawn from these data?

A) What unit of measurement was used to determine how much metal was in the soil?
B) What species of plants did you use for your remediation?
C) Since even the control plots lost metals, do I really need to remediate?
D) Since lead (Pb) is not a micronutrient for plants, how do the plants remove it?