White House. Washington, D.C. White House, formerly known as the Executive Mansion (1810â1902), the official office and residence of the president of the United States at 1600 Pennsylvania Avenue N.W. in Washington, D.C. The White House and its landscaped grounds occupy 18 acres (7.2 hectares).
Quick Answer. Ecological balance is a theory stipulating that natural conditions, including numbers of various animal and plant species, remain stable on their own through variations over time.
Ecological efficiency. Ecological efficiency describes the efficiency with which energy is transferred from one trophic level to the next. It is determined by a combination of efficiencies relating to organismic resource acquisition and assimilation in an ecosystem. Primary production occurs in autotrophic organisms of an ecosystem.