All substances take up the least amount of volume in their (1.) solid phase, a little more volume in their (2.) liquid phase, and the largest amount of volume in their (3.) gas phase. The closer atoms or molecules get to one another, the less volume is occupied by the substance that they comprise.
Human bites can be either accidental or intentional. Intentional bite injury: This generally happens during fights and can result in a wide range of injuries from minor bruising to partial loss of body parts (for example, ears or nose).
Although bed bug bites themselves aren't harmful to humans, affects of bed bug bites can cause health complications like sleep deprivation and anemia from loss of blood. Although the bites are intrinsically dangerous, the bites are itchy, and often require over-the-counter treatment to relieve the itchiness. Below is an article from Bed Bugs and Beyond detailing the deleterious affects bed bugs can have on your health, and how to relieve the discomfort caused by bed bugs.