What Did a Study of Jet Contrails Undertaken After the Grounding

question 21

Multiple Choice

What did a study of jet contrails undertaken after the grounding of commercial flights after the September 11,2001 terrorist attacks find?

• A)The study found that contrails have a very limited effect on Earth's energy budget.
• B)The study found that contrails reduce diurnal temperature ranges in regions with a high density aircraft.
• C)The study found that contrails contribute more to cloud-albedo forcing than cloud-greenhouse forcing.
• D)The study found that contrails are difficult to distinguish from natural cirrus clouds.

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Definitions:

Hypothetical Proposition

A proposition or statement that is based on a hypothesis or an assumption rather than on known facts.

Antecedent

The “if” component in a hypothetical proposition.

Hypothetical Proposition

An assumption or proposition made for the sake of argument that explores consequences of its being true, regardless of its actual truth value.

Antecedent

In logic and grammar, it refers to the conditional clause or phrase to which a pronoun refers back; in logic, also the first part of a conditional statement.