Electrical synapses, I believe.
Answer:
Es cuando los restos orgánicos son cubiertos por el suelo y con el tiempo se degradan
dejando vasios en la roca que los confinan natural mente
Global Positioning System (GPS)
Answer:
Marco polo worked as an administrator for 17 years.
Explanation:
Upon reaching China, Marco Polo entered the court of powerful Mongol ruler Kublai Khan, who dispatched him on trips to help administer the realm. Marco Polo remained abroad for 24 years
This is mutualism because both species benefit