Identify the structure indicated by the number 1 in the figure below. 
Definitions:
Auto Emissions
Pollutants released into the atmosphere from the exhaust of an internal combustion engine vehicle, which contribute to air pollution and environmental damage.
Pollution Permits
Government-issued licenses allowing the holder to emit a certain amount of pollutants into the environment.
Chicago Board
Typically signifies the Chicago Board of Trade (CBOT) or Chicago Board Options Exchange (CBOE), prominent platforms for trading commodities and options respectively.
Economic System
Represents the method employed by societies to allocate resources, produce goods and services, and distribute them amongst its members.
Q34: The loop of Henle in the nephrons
Q45: Which of the following cells act as
Q89: Which of the following groups of animals
Q97: The digestive tract is well adapted for
Q98: Through geologic history reefs have episodically been
Q104: Diseased organs can sometimes be replaced by
Q114: Endotherms have higher metabolic rates than do
Q115: Aside from whatever digestion has happened before
Q119: One of the roles of the kidneys
Q162: Which of the following statements about spermatogenesis