Difference between diffusion and osmosis

In diffusion, particles move from an area of higher concentration to one of lower concentration until equilibrium is reached. In osmosis, a semipermeable membrane is present, so only the solvent molecules are free to move to equalize concentration.

Explanation:

because of

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.