Photosynthesis, for example, is a way that plants take energy from the abiotic environment and incorporate it into the biotic environment by synthesizing sugars and proteins from it. Other components of the biotic environment, such as herbivores, eat the plants and transfer the nutrients further along the chain.
Source: Adaptec. Backplanes are the fundamental building block to any storage appliance that is meant to support hot plugging. So, SAS expanders will always go hand in hand with powerful backplanes (whether these are in a single box or not).
Tailgating, sometimes referred to as piggybacking, is a physical security breach in which an unauthorized person follows an authorized individual to enter a secured premise. Tailgating provides a simple social engineering-based way around many security mechanisms one would think of as secure. Even retina scanners don't help if an employee holds the door for an unknown person behind them, out of misguided courtesy.