To establish the correct order, we will proceed in stages:
1. Establish the subject:
The statement "as plastic pollution continues to pose a significant threat to the environment" (Q) sets the scene by identifying the core issue: plastic pollution. This naturally forms the sentence's beginning.
2. Identify the actors:
Following the problem's introduction, the relevant parties must be named. "Governments, environmental groups" (R) is appropriate here, as it designates the entities engaged with the issue.
3. Outline the measures:
Subsequently, the actions undertaken to combat plastic pollution should be detailed. "And industries are exploring the use of biodegradable alternatives" (P) specifies a concrete step taken towards resolving the problem.
4. Define the objective:
Lastly, "to reduce dependence on single-use plastics" (S) clarifies the aim or purpose behind these initiatives.
Therefore, the logical sequence is: Q, R, P, S.