Step 1: Understand the sequence of early animal development. Early animal development typically follows a specific order of events: Fertilization, Cleavage, Blastula formation, Gastrulation, and Organogenesis.
Step 2: Define each stage. Fertilization is the fusion of sperm and egg to form a zygote. Cleavage is the rapid mitotic division of the zygote into smaller cells. Blastula is a hollow ball of cells formed after cleavage. Gastrulation is the process where the blastula reorganizes into a three-layered structure (ectoderm, mesoderm, endoderm). Organogenesis is the formation of organs from the germ layers.
Step 3: Analyze the given sequences. Compare each sequence provided in the problem to the typical order of development stages described in Step 1.
Step 4: Identify the correct sequence. The correct sequence should start with Fertilization, followed by Cleavage, then Blastula formation, Gastrulation, and finally Organogenesis.
Step 5: Select the answer that matches the correct sequence. Ensure the sequence aligns with the biological process described in Step 1 and Step 2.