They avoid being detected because this would throw off the behavior patterns that exist naturally and they don't want their presence being known since this might throw it off.<span />
Can you explain it a bit better?
In the US the two houses of Congress are:
1) The House of Represenatives, lead by the Speaker of the House of Representatives
and
2) Senate, lead by the President of the Senate.
House of Lords can be found in the UK.
"House of Parliament" would not be found, as "Parliament is another name for Congress (used in other countries)
a. A 90-year-old would not likely be able to achieve an IQ of 100 using Stern's formula.