Read the excerpt from “Marine Pollution: Drifting into Disaster.” Select the two sentences that use transition words or phrases to show a cause-and-effect relationship.

The garbage patches may be hard to measure, but their effects are not. Microplastics have serious consequences for the marine ecosystem. First, when millions of tiny pieces of debris cover the ocean, the sun’s rays cannot reach beneath the surface. Therefore, plants and algae that depend on sunlight for nutrients starve. Second, fish and other sea creatures eat the debris but cannot break it down. As a result, the particles fill up their stomachs and they, too, starve. The death of sea life is a major threat to the entire ocean food web. Third, plastic waste releases toxic chemicals into the water and into the bodies of the fish that eat it.