Here are the answers to your questions:
Question 1: Which process leads to the formation of gametes?
Answer: Meiosis
Question 2: During which phase of meiosis does crossing over occur?
Answer: Prophase I
Question 3: What is the result of meiosis?
Answer: Four genetically different cells
Question 4: Which of the following increases genetic variation in sexually reproducing organisms?
Answer: Crossing over
Question 5: What is the term for the exchange of genetic material between homologous chromosomes?
Answer: Crossing over