4.
a product of the krebs cycle is
carbon dioxide
alcohol
glucose
water
6.
in the presence of oxygen and depending on the efficiency of the cell, cellular respiration can produce up to
38 nadh molecules
38 atp molecules
38 fadh2 molecules
two atp molecules
7.
oxygen is needed for glycolysis to split glucose.
true
false

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.