In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

[EX Q]: Question: Early in the development of a human fetus, the skeleton is made entirely of what? Answer: cartilage
[EX A]: Early in the development of a human fetus, the skeleton is made entirely of cartilage.

[EX Q]: Question: The body contains how many types of muscle tissue? Answer: three
[EX A]: The body contains three types of muscle tissue.

[EX Q]: Question: What is the main difference between prokaryotic or eukaryotic cells ? Answer: the presence of a nucleus
[EX A]:
The presence of a nucleus is the main difference between prokaryotic or eukaryotic cells .