So here we have a pretty straightforward example problem that wants us to select one of these four potential answer options down below that best fills in the blank to complete the sentence. And so it says that the primary cells of cartilage reside in blank. Option a says lacunae, option b says gap junctions, option c says osteons, and option d says that options a through c are all correct. And so, recall from our last lesson video that cartilage has two primary types of cells, Chondroblasts and chondrocytes. And the chondrocytes are the ones that are going to reside in chambers within the extracellular matrix called lacunae.

And so, option a, lacunae is going to be the correct answer to this example problem. Now, option b which says gap junctions, those are going to be junctions that connect the cytoplasm of 2 neighboring cells. But gap junctions are not really going to be a defining feature of connective tissues where the cells are usually spaced apart and not in direct contact with one another. So we can eliminate option b. Option c says osteons, which are actually structural units of bones that we'll get to talk more about later in our course.

But again, these osteons are not part of cartilage. So, for that reason, we can eliminate option c and then of course, we can eliminate option d as well. And so a, lacunae is the correct answer here and I'll see you all in our next video.