4 Pics 1 Word Level 1681

Answer:
Vein
Hint
What is the answer to the 4 Pics 1 Word level with Close-up of a leaf showing the lines on it, A red human vein, Human veins, and Black surface with a curved line on it?

Hint
What is the answer to the 4 Pics 1 Word level with Close-up of a leaf showing the lines on it, A red human vein, Human veins, and Black surface with a curved line on it?