Answer:If the large seed plant becomes extinct the finches with larger beaks will probably die out thus reducing the finch population
2)This will happen as their source of food is gone and thus leaving them to either feed on what there not used to or die
3)im not too sure of this but this is what i think; In Darwin's finches, those that have short beaks turned out to be an adaptation that made them more suited into poking holes in the ground and feed on grubs. Also the drought reduced the number of seeds and finches with bigger beaks were able to eat the larger and harder seeds so more of them survived.
