Which of the following sequences accurately represents the order of development?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1)- Fertilisation -zygote-cleavage-morula-blastula-gastrula .
Explanation:
- Fertilisation:The process of fusion of a sperm with an ovum is called fertilisation.
- Zygote: The haploid nucleus of the sperms and that of the ovum fuse together to form a diploid zygote.
- Cleavage: The mitotic division starts as the zygote moves through the isthmus of the oviduct called cleavage towards the uterus and forms 2, 4, 8, 16 daughter cells called blastomeres.
- Morula: The embryo with 8 to 16 blastomeres is called a morula.
- Blastula: A hollow ball of cells formed as the morula undergoes further cell division and rearrangement.
- Gastrula: Formation of three primary germ layers (ectoderm, endoderm, and mesoderm) through a process called gastrulation.
So, Option 1 correctly represents the chronological order of developmental stages.