Question

Arrange the events of embryo formation
sequentially and choose the correct option:
I. Blastocyst II. Mature embryo
III. Morula IV. Zygotic cleavage
V. Blastomeres

• A. $IV\to III\to I\to V\to II$
• B. $V\to II\to I\to III\to IV$
• C. $IV\to III\to V\to I\to II$
• D. $IV\to V\to III\to I\to II$

Answer 1

The correct option is D $IV\to V\to III\to I\to II$

A zygote is formed after fertilization. After zygote formation, the mitotic division starts as the zygote moves through the isthmus of the oviduct towards the uterus. These mitotic divisions are called cleavage. Cleavage leads to the formation of daughter cells called blastomeres. The embryo then develops into a morula. The morula continues to divide and transforms into blastocyst as it moves further into the uterus and finally develops into a mature embryo. Hence, the correct order is:
$IV\to V\to III\to I\to II$