From the ecological point of view,which one of the following assumes importance in being a good link between the Eastern Ghats and the Western Ghats?

1. A

   Sathyamangalam Tiger Reserve

   (a) Sathyamangalam Tiger Reserve. It sits in the Eastern Ghats–Nilgiri–Western Ghats junction in Tamil Nadu and is the living forest bridge for elephants and tigers between the two ghats. That corridor role is the official key.

2. B

   Nallamala Forest

   (b) Nallamala Forest. Nallamala is an Eastern Ghats block in Andhra Pradesh–Telangana (Nagarjunasagar–Srisailam). It does not join the Western Ghats, so it is not the key.

3. C

   Nagarhole National Park

   (c) Nagarhole National Park. Nagarhole is a Western Ghats / Nilgiri Biosphere park in Karnataka. It is on one side of the chain, not the EG–WG link, so it is not the key.

4. D

   Seshachalam Biosphere Reserve

   (d) Seshachalam Biosphere Reserve. Seshachalam is an Eastern Ghats range in Andhra Pradesh, famous for red sanders, not a bridge to the Western Ghats. It is not the key.

Summary. Official key is (a) Sathyamangalam Tiger Reserve. The reserve occupies the Sathyamangalam landscape that stitches the Eastern Ghats to the Nilgiris and onward to the Western Ghats. Elephant and tiger movement along this Moyar–Bhavani belt is the ecological reason the link matters. Nallamala and Seshachalam stay inside the Eastern Ghats; Nagarhole is a Western Ghats park. Only Sathyamangalam is the connecting habitat.