So here we have an example problem that says, a unicellular mixotrophic protist loses its chloroplasts, but is still able to survive. How is this possible? And we've got these 4 potential answer options down below. Now of course, recall from our last lesson video that a mixotrophic organism is an organism that is both a heterotroph, meaning it consumes its energy, and a phototroph, meaning it captures energy from the sun. And so if this organism loses its chloroplast, well, then it will not be able to perform photosynthesis since recall that chloroplasts are organelles specialized for photosynthesis.
And so if this protist cannot perform photosynthesis, then it must rely on its heterotrophic abilities. And so that means that it is going to be able to rely on engulfing nutrients and other organisms via phagocytosis. And so notice answer option b is going to be the correct answer to this example problem. Now option a is not correct because it says it relies on free-floating photosystems in its cytoplasm, but this is not going to be the case. The photosystems, recall, are going to be embedded in the membranes of the chloroplast.
So, that's not going to be correct. And of course, if option a is not correct, option d, all of the above is also not going to be correct. And option c is also not correct because it says it can use an endospore to survive without nutrients for a long period of time, but that is not what the term mixotrophic implies. So for that reason, we can eliminate option c. Option b is the correct answer, and I'll see you all in our next video.