#### Answer

a) continuous; b) continuous; c) discontinuous; d) discontinuous; e) continuous;

#### Work Step by Step

a) Velocity of an airplane during a flight can be represented by a continuous function because velocity cannot jump from a value to another all of a sudden.
b) Temperature in a room under ordinary conditions can be represented by a continuous function because temperature cannot jump from a value to another all of a sudden.
c) Value of a bank account with interest paid yearly can be represented by a function with discontinuities at the end of each year when the interest is added to the account.
d) The salary of a teacher can be represented by a function with discontinuities each time the teacher gets a raise of the salary.
e) The population of the world can be represented by a continuous function because the population cannot jump from a value to another all of a sudden.