Egg

An egg is a special type of cell that has an oocyte membrane, a yolk and an embryonic disc. The egg is of great importance in the development of life on Earth. This is the initial stage in the reproduction of animals and plants. On average, one animal or plant produces about 5 million eggs during its life. 1. How is an egg formed?

1) The formation of eggs begins in the ovaries in women and testes in men. Ovulation is the process of moving an egg from the ovary to the uterus. 1. The process of fertilization does not occur directly during ovulation. On the contrary, this requires that the sperm in the uterus connect with the egg. This is called "fertilization". When sperm reach the egg, they try to penetrate and inseminate it. They invade the egg and begin producing their own DNA. Thanks to this, a new organism is formed, similar to the maternal one. After the DNA of the embryo and mother combines, the first burst of gene activity occurs. Then, development continues until the formation of a fully formed organism. 2. The point in time in the middle of the process of egg formation is called implantation - Implantation: This is the attachment of a fertilized egg to the wall of the uterus. It occurs on average 6 days after ovulation and is considered the most important in the body. If implantation does not occur, the fertilized egg dies. Unimplanted eggs leave the uterus through menstrual bleeding. As a result of these cycles, about 40% of all eggs in the world do not complete the development process and do not show any external signs of their development. About half of the remaining eggs are fertilized and one of them will become a person, animal or plant.

**3. Why is the formation of eggs a key point in the division of living beings?** 1. Development allows an organism to adapt to new environmental conditions and evolve in new environmental conditions. An organism must develop to adapt to nutrition, living conditions, reproduction of other organisms, survival, environmental safety, etc. First, over time, life appeared on Earth - thanks to the formation of eggs, which preceded life in its most diverse forms.