ANIMAL REPRODUCTION AND DEVELOPMENT
EMBRYONIC DEVELOPMENT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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a fertilized egg dividing into two blastocysts
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two eggs being released at the same time, and both are fertilized
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two embryos implanted in the uterus through invitro fertilization
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all of these can result in twins
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Detailed explanation-1: -All pregnancies start when a sperm fertilises an egg. This fertilised egg is called a zygote. Sometimes a woman’s ovaries release 2 eggs, and a separate sperm fertilises each egg. This forms twins.
Detailed explanation-2: -Multiple pregnancy usually happens when more than one egg is fertilized. It also can happen when one egg is fertilized and then splits into 2 or more embryos that grow into 2 or more babies. When one fertilized egg splits into 2, the babies are called identical twins.
Detailed explanation-3: -However, for a given pregnancy, only the mother’s genetics matter. Fraternal twins happen when two eggs are simultaneously fertilized instead of just one. A father’s genes can’t make a woman release two eggs. It sounds like fraternal twins do indeed run in your family!
Detailed explanation-4: -Factors that increase the chance of twins include: consuming high amounts of dairy foods, being over the age of 30, and conceiving while breastfeeding. Many fertility drugs including Clomid, Gonal-F, and Follistim also increase the odds of a twin pregnancy.