Answer: 1)Spiral galaxies are a class of galaxies originally described by astronomer Edwin Hubble in his 1936 work The Realm of the Nebulae.
2) They are part of the Hubble sequence a morphological classification scheme for galaxies.
3) Spiral galaxies usually consist of a rotating disk that contains stars, dust, gas, and a concentration of stars known as the bulge in the center.
4) These bulges are often surrounded by a faint halo of stars, many of which reside in globular clusters – a spherical collection of stars that orbits a galactic core.
5) As such, Spiral galaxies are named after their spiral structures that extend from the center into a galactic disk.
6) They have spiral arms – sites of ongoing star formation that are brighter than the surrounding disk due to the presence of young OB stars that inhabit them.
Explanation:
This property is called adhesion. Hydrogen bonds hold water molecules closely together which causes water to have high surface tension.
Answer: Both groups are bilaterally symmetric triploblasts with the protostome pattern of development.
Explanation:
Lophotrochozoa and Ecdysozoa are bilaterally symmetrical clade of aminals. They are triploblastic and they possess protostome pattern of development that is to say in their embryonic development, the mouth develops first before the anus.
