Which of the following can be known by observing pug marks and fecal pellets of tiger ?

Population size.

Population size of tiger in our national parks and tiger reserves can be estimated on based of pug marks and fecal pellets.

Camera trapping has evolved from earlier methods of counting tigers by using their footprints—or pugmarks—which provided inaccurate population estimates. Before setting the camera traps, teams survey an area for the presence of tigers and other wildlife.