On the basis of the passage given above, the following assumptions have been made :
1. Fig trees can often be keystone species in natural forests.
2. Fig trees can grow where other large woody species cannot grow.
3. Sacred trees can have a role in biodiversity conservation.
4. Fig trees have a role in the seed dispersal of other tree species.

Which of the above assumptions is/are valid ?

Correct Option: (d) 1, 3 and 4 only

Let us evaluate the assumptions based on the passage: 1. The passage states that fig trees provide food when other resources are scarce and support a high density and diversity of frugivores, which aligns with the ecological definition of keystone species (Assumption 1 is valid). 2. The passage says fig trees are common in agricultural and urban landscapes where other large trees are absent, but it does not state they can grow where 'other large woody species cannot grow at all' (too broad/unsupported), making assumption 2 invalid. 3. The passage states that fig trees are considered sacred in India, East Asia and Africa, and sacred fig trees may promote frugivore abundance under human disturbance, supporting the role of sacred trees in biodiversity conservation (Assumption 3 is valid). 4. The passage mentions that under favourable microclimate, plenty of seedlings of other tree species grow around fig trees, implying their role in seed dispersal/regeneration (Assumption 4 is valid). Therefore, assumptions 1, 3, and 4 are valid. This corresponds to option (d).