When a desert lizard is on hot sand, nerves in its foot send a message to the brain. The brain analyzes this information and sends a message back through the nerves in the foot. This message tells the foot to move off the hot sand. Once the foot has moved off the hot sand, a message is relayed back to the brain. In this example, what is the first message sent to the brain? A. input
B. output
C. process
D. feedback