The correct options are
B Tigers help preserve the entire ecosystem.
C Tigers help maintain balance in the food chain.
The tiger is a unique animal. It plays a pivotal role in the health and diversity of an ecosystem. Tigers are carnivores. They maintain the balance of the food chain by consuming herbivores. If this balance is disturbed, the herbivores would increase their consumption of vegetation. This would ultimately result in the loss of forest cover. Therefore, the presence of tigers in forests is an indicator of the well being of the ecosystem.