चूजों (chicks) में प्राथमिक भ्रूणीय श्वसन अंग (embryonic respiratory organ) कौन सा है?

In which of the following embryonic stages of development does the blastocoel develop?

Which cell movement process is primarily responsible for initiating the formation of the primitive streak during avian and mammalian gastrulation?

During the embryonic development of a frog, the blastopore first appears during the: