So here we have an example problem that asks, which of the following is least likely to occur in nature? And we've got these four potential answer options down below. Now to solve this problem, we'll need to recall from our last lesson video that most living organisms need to make a trade-off between their fecundity and their survivorship. And so having really high fecundity comes at the cost of having really low survivorship and vice versa. And so with that in mind, notice that answer option a says, an organism that can produce hundreds of offspring per year and live up to 80 years old.

Now, at first glance, this might look like a really tempting correct answer option. However, it's not actually correct, because although producing hundreds of offspring per year is associated with high fecundity, living up to 80 years old actually reveals nothing about the survivorship. Instead, it only reveals information about the lifespan. And so recall once again that there's not a trade-off between fecundity and lifespan. The trade-off is between fecundity and survivorship.

And so what we're saying is that answer option a is very possible to occur in nature or possible to occur in nature, and for that reason, we can cross it off since we're looking for the option that is least likely to occur in nature and there is another option that is less likely to occur. Now answer option b says, an organism that produces fewer than 10 offspring per year and can live up to 20 years old. And once again, we're comparing the fecundity of this organism to the lifespan of the organism, and there's no trade-off between the two. So option b is a possibility in nature and for that reason, we can cross it off. So now we're between either option c or option d, which are both finally comparing fecundity to survivorship.

And what you'll notice is that answer option d says, an organism that produces fewer than 5 offspring per year, which is a relatively low fecundity, where 90% of whom survive to adulthood, which is a really high survivorship. And that's exactly what we would expect to see in nature. So for that reason, we can eliminate answer option d, since again we're looking for the option that is least likely to occur. And so this leaves answer option c as the only option and it is the correct answer, which says, an organism that produces hundreds of offspring per year, which is again associated with high fecundity, where greater than 50% of whom survive to adulthood, and that is a high survivorship, and that is unexpected in nature. And so that is why answer option c is least likely to occur.

So we can go ahead and indicate that answer option c is the correct answer to this practice example, and I'll see you all in our next video.