Answer:
An area affected by an oil spill can become unhabitable for the sea birds' source of food because of toxic poisons and in turn, make it uninhabitable to the sea birds. The animals that depend on the birds for food will have fewer available options for prey and their population may lower. If the area affected by the oil spill has low biodiversity it will have a great effect on the food web.
D, because she wants to monitor the wildlife.
Life needs energy, water, heat and nutrients. Reduce the availability of one or more of those things and biodiversity generally decreases.
Tropical forests tend to be more diverse than polar ice caps. However, arctic seas tend to be more biologically interesting than the middle of the Sahara. I bet this is what your homework is looking for but it's important to remember there are counterexamples.
Transcription - creates mRNA