Hello Melos, my name is Finch and I will critique your submission today. Sorry for the rather large critique, if anything is unclear, let me know and I'll draw it out for you.

Organic arrows

You're off to a fine start with your arrows. It's very good that you are experimenting with your arrows and finding new ways to twist and turn them in 3D space. You're not afraid to let your edges overlap and are applying perspective nicely. The only things I would look out for is where you place your shadows and markmaking. The top middle arrow (https://imgur.com/A2euekJ) that recedes into the background has the shadows placed on the wrong side, this gives it the illusion that either the arrow is becoming very small or perspective has been distorted. The second point is markmaking, while your lines are generally really good, you do tend to wobble a bit at the end of each arrow. Make sure you ghost your lines before drawing them. It might help to incorporate more ghosting and superimposed lines in your warm-ups.

Leaves

Once again, good job on getting out of your comfort zone by drawing complex leaves. Most of your leaves look good, you have a good sense of flow, the only issue I see with flow lines if the top left and top right leaf, which has quite stiff flow lines: https://drawabox.com/lesson/3/2/flowline

Remember that even the most complex leaves are made out of multiple leaf-like shapes. Take your time and construct them step-by-step to ensure that you don't accidentally make them too stiff.

You've attempted to fold your leaves, good job on that! I do see that some leaves fold unnaturally, particularly this one: https://imgur.com/6driZJe, don't be afraid to overlap lines, even if it looks weird at first.

Branches

Good attempt at the branches, but make sure that you ghost and draw confidently, since some of your branches are quite stiff. While accuracy is a goal, it can't be forced and usually comes with time and experience since it's mostly about muscle memory, getting confident lines is your main priority here. Another thing I suggest for when you do these as a warm-up, is to make the branches turn in space by varying the ellipse degrees. This is not necessarily a mistake, but it can be useful to practice: https://d15v304a6xpq4b.cloudfront.net/lesson_images/061ed3b6.jpg

If this stiffness is from being nervous, remember that it's okay to make mistakes, Drawabox is made for learning art, and making mistakes is a part of the learning process. If you feel very nervous, then it's best to take a short break and rest for a bit or do some 50% drawings, since being too nervous can be detrimental to your line quality.

Plant constructions

You're off to a good start with your first plant, your petals have a great flow to them. Two things I want to point out is the lack of degree shift in the branch and the inner zone of the flower. I have already touched on degree shifts in the 'branches' section, and the same applies here. Another thing I notice is that the inner part of the flower is a bit flat, I suggest tackling that part with a dome, just like in the daisy demo: https://drawabox.com/lesson/3/3/step2

Your second construction looks good.

Your third plant looks good, the only critique I have here is that the flower isn't really connected to the stem. I believe that this is because the stem doesn't curve into the flower, and because the inner part of the flower isn't defined quite well, you can define the inner part by giving it a contour line, as seen in the fruit and sphere in the 'common pitfalls' demo: https://drawabox.com/lesson/3/8/pitfalls

Your fourth plant has some shifts in degrees, which is good to see. I suggest adding line weight to clarify overlaps with plants like these, when you have many overlapping parts, the construction can quickly become unclear without some lineweight that clarifies what's in front and what isn't: https://drawabox.com/lesson/250boxes/1/overlaps

It's good to see you branching into using cast shadows to define forms in your fifth contstruction. The leaves are well defined and have a clearer hierarchy with the cast shadows. I suggest adding some contour lines to pots, since it can look like the plant is floating in front of it right now. As for the dirt, I suggest tackling it like a texture next time.

Your sixth construction looks good, you've started to use line weight here to clarify overlaps and it really paid off! The contour added to the inner section is good too.

Your seventh construction is really interesting, in a good way! I've never seen someone attempt a top-down view before. These plants look very solid, especially the top branch.

Your eighth construction looks good. The only suggestion I have here is to find a reference where some of the cactus 'branches' sit on the front or back of the cactus, this will give it extra solidity.

As a closing note, I suggest adding page numbers and species names with each construction. This will make it easier for people to look up the species and compare it with your contructions, which allows for a more detailed critique.

All in all, I think that you're ready to move on to lesson 4. You've showed some great improvement with these exercises! Have a nice day, and don't forget to add some of these exercises to your warm-up pool.