Facilitated diffusion is a form of passive transport utilizing membrane proteins. When is facilitated diffusion used rather than diffusion? A) Facilitated diffusion is used when energy is required for transport.
B) Facilitated diffusion is used when concentrations must be more closely controlled.
C) Facilitated diffusion is used when molecules need to move more quickly across the cell membrane.
D) Facilitated diffusion is used when molecules cannot diffuse through the cell membrane , because the lipid bilayer repels the polar molecule.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .

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.