Which of the following is a characteristic that you could look for to determine if a cell has undergone secondary endosymbiosis?

A photosynthetic organelle with 3 or more membranes.

Which of the following is a characteristic that you could look for to determine if a cell has undergone secondary endosymbiosis?

here we have a pretty straightforward practice problem that asks, which of the following is a characteristic that you could look for to determine if a cell has undergone secondary endosymbiosis? And we've got these 4 potential answer options down below. Now, of course, recall from our last lesson video that secondary endosymbiosis is when a host cell engulfs a eukaryotic cell that theoretically its ancestors have already undergone endosymbiosis. And so that eukaryotic cell that was engulfed would then live inside of the host cell and develop a symbiotic relationship with the host cell. And over a very long period of time, eventually that eukaryotic cell would evolve and develop into an organelle with 3 or more membranes. And so having 3 or more membranes is an indicator of secondary endosymbiosis. So notice that answer option b says, a photosynthetic organelle with 3 or more membranes, and that is going to be the correct answer to this practice problem. So we can go ahead and indicate that option b is correct. Now option a says a rough endoplasmic reticulum. Option c says a complex nucleus and endomembrane system, and option d says a chloroplast. However, all three of those things or all three of those answer options could also be found in cells that have undergone primary endosymbiosis. So these are not the best indicators for secondary endosymbiosis, and again, that's why we can eliminate those options and option b, again, is the correct answer. So that concludes this practice, and I'll see you all in our next video.