Final answer:
In a pedigree for a mitochondrial disease, all children of affected mothers should be affected, including both males and females. This is because mitochondria are maternally inherited.
Step-by-step explanation:
If you are looking at a pedigree that represents a mitochondrial disease, you should see that all children of affected mothers are also affected, regardless of their sex. This means that both males and females will display the characteristics of the disease if their mother is affected, because mitochondria (and thus mitochondrial DNA) are inherited exclusively from the mother. Consequently, the correct answer to the question of what you should see in a pedigree if it is a mitochondrial disease is: 3) Presence of affected females and unaffected males in every generation. However, since mitochondrial diseases are maternally inherited, option 3 is still incorrect because males would also be affected if their mother carries the disease. The description in the question is indicative of an X-linked recessive inheritance pattern, not mitochondrial. Since mitochondrial diseases are inherited maternally, all offspring of affected females would inherit the disease, whereas none of the offspring of affected males would inherit the disease from their father.