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Hi @xlaylamx

ON THE TOPIC 4
If it says ColorChallenge, then it is a Challenge. Most of these tell you what the color of the day is like yellow. So for this you could take a picture of a yellow flower and put it as an entry for the contest. Although some can be different.
Each challenge will list the Rules and that will tell you how to participate.
I hope this helps. If you have more questions, please ask. Or tell me what you would like to participate in and I will help you make sure you understand the Challenge :)