Step 1 : Introduction to the question "1. This poses a major threat to the leatherback sea turtle when ingested, and unfortunately one third of leatherback sea turtle adults have attempted to. What am I talking of?"
...1. Cigarette butts 2. Food scraps 3. Cardboard 4. Plastic bags An estimated one third of adults have tried to ingest plastic, particularly plastic bags. They confuse them for their main prey - jellyfish. Some adults have been found with over five kilograms (11 pounds) of plastic inside their stomach. The plastic can block up their intestines or lead to malabsorption of nutrients. They are particularly prone to eating these closer to urban areas, especially around California, which uses up to 19 billion plastic bags a year. While I'm sure it would be dangerous for the leatherback sea turtles to digest the other options, there is no evidence that this has actually happened.