Which of the following does NOT occur during the embryonic period? The primitive streak appears and begins to form the central nervous system. A blood vessel that will become the heart begins to pulsate. Facial features begin to form. Movements like stretching, yawning, and swallowing begin to occur.

Answers to mastering biology drag the labels to their appropriate locations to complete the punnett squares for morgan's reciprocal cross. drag blue labels onto the blue targets to indicate the genotypes of the parents and offspring. drag pink labels onto the pink targets to indicate the genetic makeup of the gametes (sperm and egg). labels can be used once, more than once, or not at all. hints