Answer:
Because Circumpolar constellations are constellations that never set below the horizon when seen from a particular location on Earth.
They can be seen in the night sky throughout the year, while other constellations are seasonal, visible only at certain times of year.
The term circumpolar refers to constellations and stars that are circling the north and south celestial poles without ever dipping below the horizon. All circumpolar constellations are found near the celestial poles and, due to their proximity to the poles, they never disappear from view.
The five northern constellations visible from most locations north of the equator throughout the year are Cassiopeia, Cepheus, Draco, Ursa Major, and Ursa Minor.
The three southern circumpolar constellations visible from most locations in the southern hemisphere are Carina, Centaurus, and Crux.
Other constellations are just as prominent in the sky and can be seen for most of the year, but only these eight are circumpolar.
to classify it as a protostome, zoologist must see for the mouth development in the embryo.
Explanation:
The protostome are the animals which are unique to their three germ layer in embryonic development, with the bilateral symmetry as they have the ability to fly with other protostome developments.
the one characteristic feature to distinguish them as the protostome, mouth part development is to be sought as the mouth develops but not the anus in the embryo. the mouth parts serves unique to the group and their feeding structures.
