What is morula?

The correct answer is Option (2) → Embryo with 8 to 16 blastomeres.

The cells formed by the first divisions of the zygote are called blastomeres. A morula is the early embryo with 8 to 16 blastomeres, stage (e) in the figure below. It later becomes a blastocyst, which implants in the uterus.

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.”

Figure 2.11 Transport of ovum, fertilisation and passage of growing embryo through fallopian tube