Question

What is the correct sequence of the following four events during an animal's development?

gastrulation
metamorphosis
fertilization
cleavage
A. 3 → 4 → 2 → 1
B. 3 → 2 → 4 → 1
C. 4 → 3 → 1 → 2
D. 3 → 4 → 1 → 2
E. 4 → 3 → 2 → 1

Answer 1

The correct sequence of events is cleavage → blastula → gastrulation → metamorphosis (Option D). Gastrulation follows, where the blastula undergoes a rearrangement of cells to form three germ Finally, metamorphosis occurs in some animals, leading to significant changes in their body structure and form.

Step-by-step explanation:

The correct sequence of the four events during an animal's development is cleavage → blastula → gastrulation → metamorphosis (Option D). After fertilization, the zygote undergoes cleavage, which is a series of cell divisions without growth.

This results in the formation of a blastula, a hollow ball of cells. Gastrulation follows, where the blastula undergoes a rearrangement of cells to form three germ layers (ectoderm, mesoderm, and endoderm). Finally, metamorphosis occurs in some animals, leading to significant changes in their body structure and form.