Which group exhibits gill slits at some stage of development?

all echinoderms

all chordates

all mollusks

all cnidarians

The correct answer is all chordates.

Explanation:

The individual opening of gills are called gill slits.Many organism such as fish and sharks which belongs to chordates family have gill slits.

   Gill slits helps in the filtration of food particle from water.Beside this gill slits helps in proper respiration or respiratory exchange of oxygen and carbon dioxide gas.

  Gill slits creates a connection with pharynx and this connection helps in the passage of water to the exterior,thereby helps in the wetting of gills.Fishes and sharks contain gills during the embryonic stage of their development.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

satellites are frequently used to make observations of the orbit on earth