Which statement(s) is/are applicable for a gas expanding isothermally against a constant pressure of 2 atm?

a. The system absorbs heat.

b. The system releases heat.

c. No heat flows.

d. Work is done by the system.

e. Work is done on the system.

f. No work is done.

g. The temperature of the system decreases.

h. The temperature of the system increases.