Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A zygote has a volume of pL. It divides without growing, and all the cells divide together.
Fertilisation takes place in the ampulla and gives a zygote with chromosomes. Cleavage gives cells after divisions, with no growth of the embryo. The morula has to cells. The blastocyst has a trophoblast and an inner cell mass. The ovum always carries X, and a sperm carries X or Y with equal chance. The trophoblast attaches to the endometrium in implantation.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Zygote: pL. No growth.
Plan. The number of cells is after divisions. Divide the volume by the number of cells.
Step 1. After 4 divisions. cells.
Step 2. After 5 divisions. cells.
Step 3. One cell after 5 divisions. .
Answer: cells; cells; pL.
Check. pL, the volume of the zygote.
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