The embryo with 8 to 16 blastomeres is called ________

The correct answer is Option (1) → Morula

After fertilisation the zygote divides by mitosis as it moves down the oviduct. This division is called cleavage, and the cells formed are blastomeres.

Option (1) Morula — Correct. The early embryo with 8 to 16 blastomeres is a solid ball of cells called the morula.

Option (2) Blastula — Incorrect. The morula divides further and becomes the blastocyst (the blastula stage) in the uterus. Its cells are arranged as an outer trophoblast and an inner cell mass.

Option (3) Zygote — Incorrect. The zygote is the single diploid cell formed at fertilisation, before any division.

Option (4) Foetus — Incorrect. The foetus is the developing baby after its organs have begun to form, from about the end of the second month.

NCERT Extract:
Fertilisation and Implantation – “… The mitotic division starts as the zygote moves through the isthmus of the oviduct called cleavage towards the uterus (Figure 2.11) and forms 2, 4, 8, 16 daughter cells called blastomeres. The embryo with 8 to 16 blastomeres is called a morula (Figure 2.11e). The morula continues to divide and transforms into blastocyst (Figure 2.11g) as it moves further into the uterus.”