What so you mean? the embryo? this question makes no sense
The pressure of the earth.
molecules
moister in the ground causes it to expand so we a drought comes in to effect and all the moister evaporates the ground shrinks and the cracks form
It causes the cell to split into four haploid cells.
It hapens erosions
A female fetus with an a y chromosome is what makes it develop differently from a male fetus.
Cigarette amoke
If the toenail is too long or if it is dry, then it will split.
Glycol Ethers that are used in fracking-Trevor
Temperatures such as freezing and thawing water causes the rock to split. Also, if something causes it to shift position and fall on another rock, it may break up.
Addiction, or ignorance of the effects on the fetus, or both.
When you chew on it. Or if your cuticals are crusty, then it will rip.
Uneven watering.
sometimes when you have a split down the middle of your toungue, its from eating many sour items,
if your rh- your anti-bodys can attack the fetus but not usually with your 1st pregnancy
The pressure of the earth.
Split ends.