Miracles happen every day and twins are one of them. At old times it has been a mystery of how twins were formed. For some ancient cultures such as Japanese culture, giving birth to twins can even be interpreted as a bad omen. But today’s science has an explanation for this marvelous phenomenon: how twins are formed.
There are two types of twins: identical and fraternal. Identical twins have the same genetic code and are formed by the split of one fertilized egg. As they are made with the same egg, they are identical. In the case of fraternal twins, things are different. Fraternal twins are formed with two eggs fertilized by two different sperms. As both the sperms and the eggs are different, they are not identical.
According to a recent research, we are having more twins than ever. This raise in the rate of twin births are explained by various factors. First factor is actually a social factor. Now more women choose to postpone marriage and having kids to a later age. As the age of the mother advances, the chance to produce more than one egg is higher.
There is also a connection between the number of births and the possibility to give birth to twins. Women who have given birth earlier have a higher chance to give birth to twins later. It may also be due to hereditary reasons of the mother.
Another factor has nothing to do with modern society and stems from race. Research suggests that black African women tend to conceive twins more than other women do. Whether this has something to do with their genetic code or it is simply a factor related to their habitat is still being debated on by scientists.
Stem from: Come from
Various: Many, numerous
Due to: Because of
According to the passage, which of the following twin type is formed by two separate sperms?
Which of the following ancient culture believes that twins mean bad omen?
Which of the following factors do not increase the possibility to conceive twins?
- Having a child at an older age
- Being from an African race
- Giving birth to many kids
- Eating identical vegetables
(4) Eating identical vegetables