What Is the Likely Connection Between the Metal Iridium and the Demise

question 155

Multiple Choice

What is the likely connection between the metal iridium and the demise of the EarthEarth''s dinosaur population?

• A) Iridium, which is found in abundance on Earth''s surface, is poisonous to reptiles.
• B) Iridium is found beneath Earth''s crust. Meteor impacts during the dinosaur age probably exposed and uncovered enough of it to poison the dinosaurs.
• C) Iridium is found in meteorites but is rare on the EarthEarth. The existence of a worldwide layer of it suggests a large meteor impact during the dinosaur age. The impact probably raised enough dust to block out sunlight and kill the dinosaurs.
• D) Iridium is highly radioactive. Its presence in a geologic layer dating to the dinosaur age suggests that natural radioactivity reached dangerous levels at that time, and the dinosaurs died from overexposure.

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Definitions:

Discriminative Stimulus

A stimulus in the presence of which a particular response will lead to a reinforcement (or punishment) in operant conditioning, essentially signaling the availability of reinforcement.

Avoidance Learning

A learning process in which an individual learns a behavior or response to avoid an unpleasant or harmful stimulus.

Aversive Event

An unpleasant or undesirable event that causes a negative reaction in an individual, often used in psychology to study behaviors and conditioning.

Organism

A living entity that can function independently, including animals, plants, fungi, microorganisms, and in some contexts, viruses.