I vaguely know about how blood is made, but what stops the body from making way too much? And if the person isn’t done growing, how does the amount of blood increase until adulthood then not keep going? I’m probably overthinking this, I just have a lot of time to think at work. Thank you.
Edit: Thank you everyone for answering my question. I really appreciated the mix of simplified and more detailed responses. This was such a great opportunity to learn from experts, and you made me want to learn more. Also, you answered my follow up questions before I got around to asking them, so thank you for that, too.