Nervous systems are required by animals to respond to stimuli and have complex senses such as taste, touch, sight, smell, or sound. these are carried by nerves to and from the brain and spinal cord. of all major animal phyla, which does not have nerves?

Porifera

Explanation: Is the correct answer for Pennfoster.

i think its the first one

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.