I have made an android app called EcoStudy (not published yet) with the basic idea of planting trees for correct answers. Much like freerice.com but for trees. I have just started working on it and there is still (a lot of) work to do. You can have a look at the screenshots to get a basic idea of the app.
I'd be glad any of you guys could have a look the screenshots and provide feedback, also as I am currently working on it by myself, I would love to collaborate for its future development. I am mainly looking for someone who I can help with UI/UX, building a database of good questions, active feedback with new features we could implement and automating the tree planting processes.
Hit me up at [email protected]
Thanks for your time. <3
Looks cool!