Most databases created today do not use the hierarchical or network models; however, these models, which are generally used with legacy mainframe systems, are still operational and so must be maintained.

a. true.
b. false.

Dereck works for long hours on his computer.  he frequently experiences physical strain by the end of the day because he does not follow an important rule of ergonomics with respect to the use of keyboards.  which of the following actions of dereck could lead to physical strain? a.  placing the keyboard exactly in front of him while typingb.  keeping hands and wrists straight while typingc.  using wrist pads throughout the dayd.  pounding at the keys on the keyboard while typinge.  resting his hands on the keyboard when he is not typing

People should never use telepresence when virtually meeting with a group of co-workers. true false

The physical parts or components of a computer system is called .