I am very happy that you've decided to do the optional homework I've assigned! This'll certainly help me to further understand your work as a whole. Now, let's get right to business.

Organic forms ellipses/curves

I can clearly see your attempt at adjusting what I've mentioned above so thank you! One thing I tend to see with your ellipses is that you're a little afraid of making them wider. I am not sure if this was right assumption to make since I have no idea what could be holding you back, but, if possible, It would be great if you could Widen your ellipses more because this'll help you out with conveying your illusion of 3dness.

This is a Demo I've done for a student in the past. You might want to give it a look!

Your curves seem to also be experiencing this issue a little bit too, but it's not as present as ellipses one. As always, the same principle that apply to ellipses also apply to curves too. (Check the image above for some example on the matter.)

Side notes : Don't forget, no matter how wrong a line is or how disproportionated a form may be, don't readjust or draw over it. Leave the line as it is as if it were correct. And also! It would be great too if you don't leave notes about your misstep in those drawing. It often serves as a distraction to a person who's critiquing you and we often ignore it to give us the ability to try our best to critique without any bias. Don't be so harsh on yourself, we all make mistake.

Form intersections

I can clearly see your effort toward making those form more equilateral, and you've also improved your intersection to be more believable also. There isn't much I would like to critique about this exercise because of how difficult it is, especially the intersection part. Overall, nicely done!