In the past, things like this were expressed in terms of individual size. For example, when I was a child, the blue whale was often said to be the largest creature in the world. However, nowadays, there are more and more cases where we recognize them as the same individual based on their DNA.
According to the Guinness Book of World Records I read a long time ago, this was the world's largest plant.
That's a redwood tree . You can see its size when you compare it to the woman. There are still theories that it is the world's largest plant. Well, I suppose that's one correct answer. However, from the perspective of DNA, as mentioned earlier, this is the correct answer.
This is a mushroom called Armillaria mellea . When DNA analysis was conducted on this mushroom in Oregon, USA, it was found that all the individuals growing in a cluster over an area of just under 9 square kilometers were identical.
It might seem like a bit of a stretch, but some argue that this is the world's largest.