Answer:
I don't think it was because your room wasn't clean. The main cause of bed bugs is travel, which means most likely you got one on you when you went outside or something, and you accidentally got it into your room. Bed bugs hitchhike on luggage, clothing, people, etc.
If there are blood stains or dark/rusty spots on your bed/pillow, there are definitely bed bugs. The bloodstains/spots come from you crushing the bed bugs accidentally. The place where bed bugs are (in this case, your room), may also begin to smell bad. You might also see eggs laid by the bed bugs.
Let me know if you have any other questions. Good luck!
Answer:
I don't understand your question may be questioned mistakes
In geology, a graded<span> bed is one </span>characterized by<span> a systematic change in grain or clast size from one side of the bed to the other. Most commonly this takes the form of normal grading, with coarser sediments at the base, which grade upward into progressively finer ones.</span>