For What Purpose Would a Microbial Ecologist Use a Microsensor

Multiple Choice

For what purpose would a microbial ecologist use a microsensor?

A) to determine the concentration of cells in small increments in a sediment or water column
B) to determine the expression of a particular gene in a microbial community
C) to quantify the uptake of a radioactive material
D) to determine the concentration of O₂, N₂O, or other chemical species in small increments in a sediment or water column