Answer:
1. 4
2. 1
3. The egg
Step-by-step explanation:
1. The diploid cell undergoes 2 rounds of cell division (meiosis I and meiosis II). The diagram shows that at the end of meiosis I, there is two diploid cells (2 copies of DNA). However, after meiosis two, there are 4 cells with a haploid genome (1 copy) that go on to become mature sperm cells. Think of it like a cell with 2 copies doubles itself and splits in half during meiosis 1 (to create 2 diploid cells). These cells split in half again without doubling, producing 4 cells with half the amount of DNA.
2. The logic is the same as the above to produce 4 cells, but what happens to these cells is different. The process is the same, the DNA is replicated and divided as if 4 gametes were going to be made, but instead, 3 out of 4 of the cells do not become functional gametes, they become something non-functional called polar bodies that are typically absorbed by the largest cell. The first of these is produced after meiosis I, where only 1 functional diploid cell is produced. The second and third polar bodies are produced after the second meiosis, where only 1 functional haploid gamete is produced. See the attached picture for an example.
3. The egg cell is much larger than the sperm cell. The egg cell is the largest cell in the human body, and in fact, the sperm cell is the smallest! The egg is around 40x bigger than sperm