ANNEX 1 WORKING DEFINITIONS OF KEY TERMS

Adolescence The period of life beginning with the appearance of secondary sex characteristics and terminating with the achievement of full maturity (usually 12-18 years of age). 

Adult The time of life usually starting at 18 years (some systems such as skeleton and brain may continue to develop). 

Adverse effect A treatment-related alteration from baseline that diminishes an organism s ability to survive, reproduce, or adapt to the environment. 

Aggregate risk assessment The evaluation of risk from exposure to a given chemical from multiple routes of exposure. 

Critical period A specific phase during which a developing system is particularly susceptible. 

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