A. Small molecules easily pass between the phospholipids in the cell membrane. B. Substances move from an area of low concentration to an area of high concentration.
C. Transport proteins use energy to push large molecules across the cell membrane.
D. A vacuole opens to release substances into the area outside the cell.

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.  

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

catya that's not even a b or c