Two rejected photos, but why :c

In addition to George's very useful comments about the technical flaws, the hamburger image is not well composed. Neither burger is in full view, and the background is cluttered. If you search the database for"hamburger" you will find more than 600,000 images which will give you an idea of the desired quality. 

https://stock.adobe.com/search?load_type=search&native_visual_search=&similar_content_id=&is_recent_search=&search_type=usertyped&k=Hamburger+

I can say about the second photo: the photo is almost completely out of focus. The front of the hamburger, which is important and the first thing that catches the eye, is not in focus at all.

Photography with a smartphone is accepted, but remember that the same level of quality is still expected by the reviewers.  When I zoom in to 100% in Lightroom, the flaws are noticeable.

The burger photo had too shallow of a depth of field and not too much was in focus, there was quite a bit of noise, and a yellow colorcast.

The sunrise photo was underexposed, and there was noticeable noise & artifacts in the sky.  If you correct the underexposure and fix the noise in the sky, this one may squeak through.  I would search for a similar type of photo in Abobe Stock first to see how the competition stacks up first though, to get a realistic idea of whether this photo will sell or not.

I hope this helps!