President barak obama issued two documents related to critical infrastructure that increase the national focus on issues of security and resilience. these two
documents are:
select one or more:
a. presidential policy directive-21: critical infrastructure security and resilience.
b. presidential policy directive-2: implementation of the national strategy for countering biological threats.
c. executive order 13636: improving critical infrastructure cybersecurity.
o d. executive order 13616: accelerating broadband infrastructure deployment.

The constant presence of diseases or infectious agents within a given geographic area or population group. it may also refer to the usual prevalence of a given disease with such area or group. it includes holoendemic and hyperendemic diseases. a holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). a hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. so probably family history.