What is optical density and how is it different from mass density ?

Distinguish between physiological and agricultural density. How are they different from the density of a country?

Physical density and optical density

Find out from table 10.3 of the text-bool, the medius having highest optical density. Also find the midum with lowest optical density?

What is population density ? Explain any three different ways the population density can be measured with the of an example of each.

What is ecological density, crude density and population density ?

Find out from table ,the medium having highest optical density. Also find the medium with lowest optical density.