Arrows

Pretty good job in general, only issues I can see is that they are a bit wobbly, so remember that every mark you do should be confident (It's always more important to make a mark confident than accurate, so don't hesitate to sacrifice accuracy to make your lines more confident), and that they aren't growing much. Try to exaggerate how the arrows get bigger as they get closer to the viewer.

Organic forms

Pretty good job in general, some of them are bulging a bit, so remember tha they should be simple, just 2 identical balls connected by a tube of consistent width.

Textures

Pretty good job, you're focusing on cast shadows, transitions on the gradients are p good too, and the textures on the dissections wrap up quite nicely, you're also making a good use of the silhouette to show the textures better.

Form intersections

Pretty good in general. You've a few lines that are a bit wobbly, and remember that the main objective of this exercise is to draw forms in the same scene in a cohesive manner, by mantaining a consistent foreshortening on them. To do that, it's easier to accomplish it by drawing shallow foreshortening forms, so try to focus on them on your next exercises.

Organic intersections

They feel pretty good in general, try to stick to simple forms (you've got a few complex ones there) but other than that, they feel pretty 3d