Your arrows have a very inconsistent width, which makes it a bit hard to understand which side is closer to the viewer. They should consistently get smaller as further it goes (but not have a wobbly variation).

Your sausages are nice. You got more degree variation on your curves than on the ellipses, so I think you got the idea but couldn't really apply it with ellipses.

The texture studies show that you understood them, but i think you had a bit of problem drawing on the lighter side of the texture. You can try and work a bit more implicitly, drawing only the shadows, not caring too much about the shape itself. That's more noticeable in your feathers, which look good, but are very explicit.

You dissections are very good. I like how you took every possibility to break the silhouette of the form.

The forms on the form intersection exercise are well done. I'd advise you to try drawing the back part of the intersection (the side we shouldn't see), so that the intersection is really visible through the forms.

The organic intersection is nice, the shadows and contour lines really give it a 3 dimensional form.