Answer:
Number of sentences that have comma error is one. Only first sentence have comma error.
Step-by-step explanation:
Comma is one of the punctuation mark which is used before conjunctions or after a dependent clause. Comma is used when we have to take a slight pause and is also used to separate items in a series. The proper usage of comma in the given sentences is:
1. When daughters of Queen Victoria of England, who carried the gene for hemophilia married royalty in Germany and Russia, those royal families inherited hemophilia as well.
All the other sentences have made a correct usage of comma. The second, third, and fourth sentences do not require comma because they are just a simple sentence without any conjunction.