Which best describes energy? a. once energy is used, all living organisms must make more. b. energy can only change forms. c. energy can only be transferred. d. energy can change forms and be transferred.

Option D, Energy can change forms and be transferred.

Explanation:

As per law of conservation of Energy,  Energy is neither created nor destroyed. However, it can only be transformed from one form to another. Also energy can be transferred from one substance  to another.

For example -

In the process of photosynthesis, energy of sun is transferred to green plants and trees which later convert the radiant energy of sun into chemical energy.

Hence, option D is true.

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.

d. cellulose and starch