20. There are two basic steps that take place when forming an ionic bond. a) The formation of
due to the transfer of electrons between
two atoms. In our example of sodium chloride (NaCl), sodium (Na) only has
electron in its valence shell and a lower electronegativity than
chlorine (CI), so Na will lose its valence electron to Cl. This produces a sodium
ion, with a
charge (Na+1). Chlorine has
electrons in its
valence shell and because of its higher electronegativity, gains an electron from
Na. This produces a chloride ion with a
charge (Cl-).
b) Once the ions have formed through the transfer of electrons, the
charges of the ions are attracted to one another, forming the
ionic bond.

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i think it is d. objects resist changes in their state of motion.

answer: the correct option is d. enzyme

lactase and carbonic anhydrase are the examples of enzymes.

lactase is an enzyme, which is present in the small intestine of mammals. it in the digestion of the disaccharide, lactose ( milk sugar) by converting it into two monosachharide, which are glucose and galactose.

carbonic anhydrase is present in the red blood cells. this enzyme plays significant role in the transport of co₂. it in the conversion of co₂ and h₂o into carbonic acid, which is then dissociated into bicarbonate ions and hydrogen ions.