Some people often ask why people have singles? Now, a biology teacher, let’s briefly spread your questions. [1] Let’s first understand what fertilization is.

Some people often ask, why do people have single babies? twin? Why do some twins look almost exactly the same? And some twins look different? Why are there " twins "?

Twin fetus

Now, biology teacher, let’s briefly spread your questions.

【One】Let me understand what fertilization is.

The process of combining sperm with egg cells is called fertilization.

After the egg cells are discharged from the ovaries, they enter the fallopian tube. Sperm can pass through the uterine cavity and reach the fallopian tube by relying on its own movement. At this time, if the sperm and egg cells meet, they may be fertilized.

[Two] Causes and processes of single cells:

During the fertilization process, generally only one sperm enters the egg cell, and the same egg cell nucleus fuses to form a fertilized egg. Other sperm gradually atrophy and dissolve.

This fertilized egg develops into an embryo and gives birth to a new individual, which is a single.

【Three】The causes and processes of the formation of one-egg twins:

If a fertilized egg is cleaved and developed during the process of development, it may also develop into two embryos for some reason, forming two new individuals. This type of twin is called an egg twin.

One-egg twin sister

【Four】The causes and processes of formation of two-egg twins:

If the ovary discharges two mature egg cells at the same time, and both of them undergo fertilization process to form two fertilized eggs, it will develop into two embryos in the future and produce two new individuals, which is what is commonly known as twins. This type of twin is called a biovular twin.

2-egg twin siblings

【Five】Understand the difference between an egg twin and a two-egg twin:

Since the two new individuals formed by an egg twin have the same genetic material, the two new individuals have the same gender (that is, both are male, or both are female, and the appearance and personality are almost the same, while the two new individuals formed by two egg twins have the same genetic material (that is, both are male, or both are female, and the appearance and personality are almost the same, while the two egg twins formed by two egg twins have the same gender (that is, both are male, or both are female. New individuals may be the same in gender or different, and their appearance and personality are also different.

happy twins pregnant women

[Six] Invite you to answer:

Seeing this, you should understand, are "dragon and phoenix twins" one-egg twins or two-egg twins?