The formula to calculate population density is a. land area divided by number of populations b. number of populations divided by land area c. number of organisms in a region divided by land area d. land area divided by number of organisms in a region

c. number of organisms in a region divided by land area

Explanation:

A population density is a demographic parameter. It is define as the number of individuals of the population of species living in a particular area of the region in a particular period of time. The population density can be affected by the mortality rate or death rate, immigration rate, emigration rate and birth rate.

The mortality rate or death rate is the number of individuals of the population of species die in an area in particular time.

The birth rate can be define as the number of live births in the population of species in a particular area in a particular time.

The immigration rate can be define as the number of individuals of the species migrated from the native place in a particular time.

The emigration rate can be define as the number of individuals of the same species arrived to the given place in a particular time.

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digestion

it excretes wastes