Final answer:
During embryonic development, the correct sequence is gastrulation, followed by differentiation of tissue layers, chorion formation, and finally placenta formation. Option d is the correct answer.
Step-by-step explanation:
The sequence of events during embryonic development is crucial for forming the structures necessary for a functional organism. After fertilization, the first significant stage is gastrulation, a process where embryonic cells form three primary germ layers: the endoderm, mesoderm, and ectoderm. These germ layers subsequently undergo differentiation, where cells become specialized into various tissue types and organs.
While this is happening, the development of the chorion begins, which will eventually be part of the placenta, providing nutrients and support to the growing embryo. Hence, the correct sequence of these events is as follows: Gastrulation, differentiation of tissue layers, chorion formation, and finally placenta formation. The correct option in the final answer to the question 'Which of the following lists the events occurring during development in the correct sequence?' is d. Gastrulation; differentiation of tissue layers; chorion formation; placenta formation.