Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Narayan singh
Yes ecosystem is also a important topic. in this topic you should study ecosystem pyramid of biomass , energy, efficiency of ecosystem, energy transfer between ecosystem, biomass change in ecosystem in different levels. etc