While taking an american history exam, marie was surprised and frustrated by her momentary inability to remember the name of the first president of the united states. her difficulty most clearly illustrates failure.

the use of electrical signals that transit messages is know as

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.

answer; differentiation;

answer; develops policy;