Question

the addition rule of probability can be defined as...

the probability that two or more independent events will both occur.

the probability that two or more independent events will both occur in the offspring of one set of parents.

the probability that either one of two mutually exclusive events will occur.

the probability of producing two or more heterozygous offspring.

Explanation:

The addition rule of probability is used for mutually - exclusive events. Mutually - exclusive events cannot happen at the same time. The formula for the addition rule of probability for two mutually - exclusive events \(A\) and \(B\) is \(P(A\cup B)=P(A)+P(B)\), which gives the probability that either \(A\) or \(B\) occurs.

• The first option is about the probability of independent events both occurring, which is the multiplication rule (\(P(A\cap B) = P(A)\times P(B)\) for independent \(A\) and \(B\)).
• The second option is also related to the joint probability of independent events (similar to the first option but in the context of offspring, still a multiplication - rule - like concept).
• The fourth option is about the probability of a particular genetic outcome (heterozygous offspring), which is not the addition rule.

Answer:

the probability that either one of two mutually exclusive events will occur.