The Dose of an Antigen That Kills 50% of Animals

question 6

Multiple Choice

The dose of an antigen that kills 50% of animals in a test group and is used to estimate the virulence of a pathogen is known as

• A) Antigen dose₅₀.
• B) Virulence-50.
• C) LD₅₀ (lethal dose₅₀).
• D) Death rate-50.

---

Definitions:

Operant Conditioning

An educational method where the intensity of an action is altered through rewards or penalties.

Shaping Procedure

A method of positive reinforcement of behavior by which successive approximations of a desired behavior are reinforced.

Primary Reinforcer

An innately reinforcing stimulus, such as one that satisfies a biological need.

Conditioned Reinforcer

A stimulus that gains its reinforcing power through its association with a primary reinforcer; also known as a secondary reinforcer.