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.
A large, retrospective series examining human bite wounds in children found that none of the bites manifesting as abrasions became infected, while the rate of infection was much higher in bite wounds that caused punctures or lacerations.
Humans have a large effect on the world. Humans are at the top of the food chain and are generally not eaten by any animals. Humans have been described as Super Predators because of this. Because of industry and other reasons humans are said to be a big cause of global climate change.