Photos Rejected Quality Problems

Your photos need post procesing. Lighting, color, sharpening and cropping.
For instance:
 

Hello,

In my opinion, take more care with your composition. 

Don't always take portrait orientation; you can also take landscape-oriented photos with smartphone cameras. The portrait orientation is a dead giveaway that it was taken with a smartphone camera! This is where orientation also plays a role in composition!

Composition:
https://www.adobe.com/creativecloud/photography/discover/photo-composition.html

Read your Stock Contributor User Guide. 

Adobe Stock customers expect the highest visual and technical quality for use in commercial projects.

• https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
• https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html
• https://helpx.adobe.com/stock/contributor/user-guide.html/stock/contributor/help/photography-illustrations.ug.html
• Similar Content: 
  https://helpx.adobe.com/stock/contributor/help/how-to-submit-distinct-content.html
• Property Releases:
  https://helpx.adobe.com/stock/contributor/help/property-release.html 
• Known Image Restrictions: 
  https://helpx.adobe.com/stock/contributor/help/known-image-restrictions.html

Hope that helps.

IMG_3176.jpeg - underexposed shadows

IMG_3185.jpeg - spider isn't sharply focused 

IMG_3154.jpeg - focal point is the leaves in the foreground rather than the lizard