Starting with your organic intersections, overall you're doing a pretty good job of establishing how these forms relate to one another in space, and how they pile up under gravity. There's one key thing that I want to warn you against however.

Right now your approach for these is to create an underdrawing - that is, drawing your forms with a much fainter mark - then to go back over it all with a clean-up pass. Sometimes students confuse this with the application of line weight, but line weight itself serves a very specific purpose - to clarify particular overlaps in localized areas, and it's limited to where those overlaps occur rather than being used to effectively replace the entire silhouette of a given form. While this overall approach isn't inherently wrong, it is something I mentioned should not be used in this course back in the form intersections exercise. Reason being, it both undermines the focus of our drawings throughout this course (they are after all exercises in spatial reasoning, the goal is not to create pretty drawings), and it also can cause us to hesitate a lot more as we trace slowly along the linework, focusing on how those lines sit on the flat page, rather than how they represent edges that move through 3D space.

So, moving forward, just keep that in mind.

Continuing onto your animal constructions, there are a few things I'd like to point out, but as a whole you've done a very good job building up solid structures and considering how the forms relate to one another in most cases.

Starting with head construction, towards the beginning with your birds, you had a tendency to have your facial elements - mainly the eye socket and the beak - float separately from one another, resulting in a less structurally sound result that didn't really convey the impression that what we're looking at is 3D. As you progressed through the homework, you did improve upon this, although I do think really pushing the idea of how the different components of the head "wedge" together like pieces of a 3D puzzle would be beneficial.

This informal demo - which, by the time my course overhaul reaches lesson 5 will be the basis of how I approach head construction in any future videos (that is if catastrophic things like my apartment flooding and having to move out for 2 months while they do repairs stops delaying said overhaul) - explores the kind of methodology should be used when thinking about head construction. Overall I don't necessarily get the impression that you read it (it is linked at the top of the tiger head demo, because despite its informality it supercedes it), so definitely take a moment to do so. The key focus is on how all the pieces fit together, and how it breaks the cranial ball's smooth surface into a series of distinct planes. Also, pay attention to the shape of the eye sockets - a pentagon with the point facing downwards provides an excellent wedge shape for the muzzle to fit in, and a nice flat table for the brow ridge to be rested upon.

Moving onto your main body construction, overall you've done a great job of working with solid, 3D forms, and building them upon one another to achieve greater complexity, but there are some places where you take shortcuts, adding flat shapes into your drawing, or just leaving your 3D forms half-drawn or not fully closed. Doing so is risky, and should be avoided throughout this course. These drawings are all exercises in spatial reasoning, so we want to take every opportunity we can to build up more 3D forms and to define the relationships in 3D space between them.

So for example, if you look at this camel's back leg, the segments of that leg are individually not closed. They sit against other shapes/forms to close themselves off, but individually they are not. As a whole you really should be applying the sausage method more strictly here to construct a basic underlying armature. As I explained back in the critique of your lesson 4 work, once it's in place, you can build upon it as needed to add bulk and achieve varied forms. Starting with that sausage structure however allows us to lay down a structure that maintains both solidity and a sense of fluidity that is extremely useful. Just be sure to apply all the steps of the sausage method - from sticking to simple sausage forms, to reinforcing the joint between segments with a contour line and avoiding placing superfluous contour lines along the length of the individual segments.

The last point I wanted to make comes down to how you draw your additional masses. While you're headed in the right direction here, this is one of those areas where the specific design of your masses matters, and pushing to have them really "grip" and wrap around the existing structures pays off immensely. Here's what I mean - by exaggerating how those forms actually wrap around the structure, we can create a more solid result - rather than the impression that the humps just kind of sit on the camel's back, ready to slip off at any point.

One thing that helps with the shape here is to think about how the mass would behave when existing first in the void of empty space, on its own. It all comes down to the silhouette of the mass - here, with nothing else to touch it, our mass would exist like a soft ball of meat or clay, made up only of outward curves. A simple circle for a silhouette.

Then, as it presses against an existing structure, the silhouette starts to get more complex. It forms inward curves wherever it makes contact, responding directly to the forms that are present. The silhouette is never random, of course - always changing in response to clear, defined structure. You can see this demonstrated in this diagram.

Looking again at your camel, you'll notice that I emphasized the big shoulder and hip masses - those are the big engines that help animals walk around. They're not always obvious, but often times not hard to spot if you know to look for them. Considering their presence gives us something to then push our additional masses against, creating more of a 3D puzzle of pieces all fitting together - similarly to the head construction, if a bit more organic.

Aside from those issues, I think you are doing a great job at this, and I feel fairly confident that you'll be able to implement that advice quite well on your own. As such, I'm going to go ahead and mark this lesson as complete.