Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Question: Smog is a visible form of what? Answer: air pollution
Smog clouds the city of Los Angeles, California. Visible air pollution in the form of smog is a sign that the air is unhealthy.

Question: The enteric nervous system provides intrinsic innervation, and the autonomic nervous system provides this? Answer: extrinsic innervation
layers: mucosa, submucosa, muscularis, and serosa. The enteric nervous system provides intrinsic innervation, and the autonomic nervous system provides extrinsic innervation.

Question: What protects a developing flower while it is still a bud? Answer: sepals
Sepals protect the developing flower while it is still a bud. Sepals are usually green, which camouflages the bud from possible consumers.