Answer: offshore drilling
Step-by-step explanation:
The offshore drilling is a process of extracting the petroleum beneath the Earth's oceans. The great barrier reef is affected by the offshore drilling. The oil pollute the oceanic water.
When oil comes in contact with the corals, it can restrict their reproduction, growth and can even kill them. The whole reef ecosystem get affected by the oil extraction process, animals like fish, marine invertebrates and crabs are affected by this.