Supported. In the discussion of Temple’s critics, the author never indicates that these critics have identified why the pit walls have evolved, so the author would likely agree that these critics haven’t definitively identified the cause of the evolution of the durable pit walls.

Supported. The author does say that only a minority of the unabraded seeds germinate. While the number of seeds that germinate is sufficient to avoid extinction, it could still be true that the low germination rate due to the thick walls has led to population decline. In other words, the author recognizes that this possibility hasn’t been definitively discredited.

Unsupported. The author never indicates that we should expect the population of Calvaria major trees to be abundant. We know that the germination rate is low, and the author cites several factors that could be responsible for Calvaria major population decline. The author clearly recognizes the population decline, so we can’t support the claim that the author is surprised that the tree isn’t abundant.

This is supported in P4. We see that the number of seeds that germinate is sufficient to prevent extinction, so the author likely agrees that the tree isn’t threatened with imminent extinction.

This is supported in P4, where we see that some unabraded seeds do germinate, which shows that they can germinate even if they don’t pass through a bird’s digestive system.