 So let's just go over this picture problem. I know these ones are semi-annoying sometimes, but it's good to every once in a while do them. So this question asks, well, label each picture as one of these choices, okay? So obviously since we have five choices in six pictures, one of the choices can be used more than once, or at least one. Okay, so if you guys want to help me, you're more than welcome to. So what I would do is just look at these choices and try to measure them, right? So we've got first choice is a gaseous compound. So a compound is two or more elements stuck together, right, bonded together. So we're assuming I guess maybe we should write this here. That blue is one element and orange is another element. So we've got one bonded together. Looks like we've got here is a gaseous compound. You can see here we've got a gaseous compound, but it's in a mixture with this other thing, okay? Same thing here. We've got that gaseous compound, but it's inside of the picture. Okay, so that one looks like the only one. So a mixture of two gaseous elements. So remember an element is just one atom by itself or it can be a diatomic element where it's got two atoms of the same type of atoms stuck together, two or more, okay? A diatomic or a polyatomic would be more. So let's see what we've got here. Well, here we've got single atoms by themselves, but again they're in the mixture of that compound. Here we've got single atoms, but they're in a mixture with other single atoms, so obviously not at one of those is the case, but up here it looks like we've got atoms of the same type that are bonded together, so like a diatomic element. So we're looking for a mixture of two gaseous elements, so this one would be it. Sorry about that. I forgot what we were looking for, okay? So a solid element, of course, solids don't fly around, so the only one that makes sense for that one would be the one where all of the atoms are stuck to the bottom of the container. So a mixture of a gaseous element and a gaseous compound. Well, here, right, we've got that gaseous compound that we found earlier, and we've got a gaseous element, okay? Here we've got just two gaseous elements, but here we've got a gaseous compound, right, that we found earlier, and we talked about diatomics being elements, so this one and this one would both be represented by d, okay? Or can be representations of d, I should say. And then what's left is just the gaseous element, and it looks like the only one that can be d is that one because everything else up there. These ones are mixtures, and these ones are pure substances, but this one's compounded, of course. So let's just identify that since we've got the video rolling. These ones over here, these are all mixtures. You can see we've got one type of thing mixed with another type of thing. One type of thing, one pure substance mixed with another pure substance. All of these other ones, these are all pure substances. Even though this is atoms of two different types of elements, they're combined in the same ratio as everything else is in that same container. So this is like a pure material like carbon monoxide or something. Is there any questions about this one? If you're reading on chapter four, you guys probably have this nailed down. Okay, thank you.