Final Answer:
Sentence C, "Adult turtles also frequently got caught in fishing nets during their ocean migrations," least supports the main idea of the first paragraph.
Step-by-step explanation:
The first paragraph primarily focuses on the threats faced by Kemp's ridley turtles and the decline in their population. Sentences A, B, and D contribute to this main idea by discussing factors such as nesting behaviors, population decline, and conservation efforts. However, sentence C deviates from this central theme by introducing a different aspect—the issue of adult turtles getting caught in fishing nets during their migrations. While this is indeed a threat to the turtles, it doesn't directly align with the main focus of the paragraph, which revolves around factors contributing to the decline in Kemp's ridley turtle population.
Sentences A, B, and D are cohesive in discussing the nesting behavior, population decline, and conservation measures related to Kemp's ridley turtles, all supporting the primary theme of the paragraph. In contrast, sentence C introduces a separate concern related to adult turtles being caught in fishing nets, diverting the focus from the main idea. Although the entanglement of adult turtles in fishing nets is a valid issue, it is not directly connected to the nesting behaviors, population decline, or conservation efforts discussed in the paragraph, making it the sentence that least supports the paragraph's main idea.