Which of the following cases can be easily determined by utilizing a…

The correct option is (d) Population density of tigers, assessed through pug marks and fecal pellets in a specific area.

In the case of tiger census, non-biological parameters such as pug marks (footprints left by tigers) and fecal pellets (droppings) are used to estimate the population density of tigers in a particular area. These non-biological parameters provide indirect evidence of tiger presence and can be easily observed and recorded. By analyzing the distribution and abundance of these indicators, researchers can estimate the population size and density of tigers without physically counting each individual tiger.

On the other hand, options (a) Fish density and (b) Density of bacteria in a culture plate require biological parameters for accurate determination. Fish density often requires techniques such as netting, trapping, or underwater visual surveys to count and estimate the number of fish individuals in a given area. Similarly, determining the density of bacteria in a culture plate involves counting the number of bacterial colonies or using microscopic techniques to assess bacterial abundance.

Option (c) Population density of Siberian cranes in Bharatpur wetlands may involve both biological and non-biological parameters. While non-biological parameters such as visual observations and habitat assessments can provide some insights into population density, a more accurate estimate may require direct counting or monitoring of individuals through surveys or tracking methods.

Overall, the use of non-biological parameters can provide a convenient and indirect approach to estimate population density in certain cases, particularly when direct counting of individuals is challenging or time-consuming.