instruction:
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.
question:
Question: What holds ionic and covalent compounds together? Answer: electrostatic attractions
answer:
Electrostatic attractions holds ionic and covalent compounds together.


question:
Question: What begins approximately six weeks after fertilization in an embryo? Answer: ossification
answer:
Ossification begins approximately six weeks after fertilization in an embryo.


question:
Question: The cells in the follicle undergo physical changes and produce a structure called a what? Answer: corpus luteum
answer:

The cells in the follicle undergo physical changes and produce a structure called a corpus luteum.