Homelessness and the Universe

I went to visit a school today.
6 hours of talking to 5 classes, 5th and 6th graders, about the big bang, black holes and all the wonders of the universe. They have prepared questions given to me in advance so I could sort them by topics. I read the name on the card, read the question and answer it with props (M&M chocolate candies are a big help to explain the different "colors/energies" of photons...).
In one class I notice a girl who sits by herself in a corner of the table. She asks a lot of questions and seems to speak with difficulty. She stutters at time, does not finish her sentences. She goes from one question to the next in a endless string of words, as if she could not get enough said in the small amount of time that I gave her.
I try to slow her down, pacing her questions to no avail. I answer to the best of my knowledge and skip some of the many, many questions she asked, in order to answer questions from the other kids.
At the end of the 50 minutes allocated by class, as one kid had come up to me to give me a hug, she stands there, with an accusatory tone in her voice "Why haven't you answered my questions?" I try to explain that I did partially, that there were too many questions from other kids to answer them all. She looks at me with a defiant air, not convinced by my answer, turns around and leaves the classroom.
The teacher later on will tell me that she is homeless, living in a shelter nearby where the school bus picks her up every day. Because of this, she says, the kid requires more attention, she needs to feel that she matters to someone.
I'm not sure why but what stuck with me for the rest of the day was the vision of a yellow bus waiting for a little kid in front of a homeless shelter.