It’s science, the subject is light and color

23: Moonlight comes from the sun. Light from the Sun bounces off of the moon and travels to earth, thus creating moonlight.

24: The sky appears blue because blue light waves bounce off of particles in the sky and into our eyes, this causes us to see the sky as blue.

25: a transparent object would be a clean window. Transparent objects allow light to pass through without being disturbed. A frosted window or a dirty window is translucent. Translucent objects allow some light to pass but not all. An  opaque object would be light blocking curtains. opaque objects do not allow any light to pass through them.

chordata is the answer

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).