(xvi) Give a reason for each of the following:
(a) Cattle avoid browsing on Calotropis plant.
(b) DNA cannot enter directly into the host cell.

Solution

(a) Calotropis produces a milk like chemical toxin called cardiac glycosides that affect the heart hence cattle avoid browsing on this plant.
(b) As DNA is hydrophilic in nature and the cell membrane or plasma membrane is hydrophobic in nature, so this membrane does not allow DNA to enter in it.