The respiratory systems of birds are very efficient at providing oxygen to the blood, which is necessary for birds to expend the energy necessary
to fly. What feature of the bird respiratory system makes it more efficient than the respiratory systems of other animals?
A
a one-way air flow through the lungs and airways
B. a two-way air flow through the lungs and airways
C. bubble-like alveoli for gas exchange in the lungs
D. many tracheal tubes that connect the lungs to the skin

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.

if, i suppose that a bee stings me swinging my hand away from a bee. then that if, i persist patient when a bee or wasp areas on your surface to investigate a scent or to take h2o and i secreting heavily, the bug ultimately will move of its personal agreement. if i don't need to set for it to disappear, lightly and gently wipe it off with a part of the paper.