Population density is calculated by a. dividing the number of organisms in a region by the land area
b. multiplying the number of organisms in a region by the land area
C. dividing the land area by the number of organisms in the region
d. by subtracting the land area from the number of organisms in a region

A). Dividing the number of organisms in a region by the land area.

Explanation:

The formula for calculating population density PLUS example:

this protocol provides a detailed procedure for total protein extraction for western blot analysis from achieved samples following trizol isolation of rna.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.