Q: Respiratory development in the embryo begins around week 4. ectodermal tissue from the anterior head region invaginates posteriorly to form olfactory pits, which fuse with endodermal tissue of the developing pharynx. an olfactory pit is one of a pair of structures that will enlarge to become this? A:

-anal cavity; -eye cavity; -fluid cavity; -nasal cavity;
The answer is:
nasal cavity