CATDOLL : CATDOLL: Why is the sword water flea not a single-celled organism?

In the egg yolk. This is the yolk cytoplasm, which is the main component of the embryonic development when nutrients. Mung beans in the white yolk as large dots, called ovules, which are located in the egg. Under the right conditions from here the fertilized egg begins to develop into an embryo. The yolk membrane is a membrane protein, the egg and the eggshell are formed by the secretion of the oviduct. There is nutrition and protection. If the egg is not fertilized, the egg is a cell; but if the egg is fertilized, the situation is completely different. When the fertilized egg leaves the mother, it has already developed in the oviduct cleavage, blastocyst, gastrula, etc., then this is not a cell of the egg.