Answer:
land subsidence,sinkholes,freshwater contamination and having to dig deeper and deeper irrigation wells
They observe it, run tests on many different things, and do expirments
The three mechanisms which regulate the heart are endocrine, cardiovascular and Sinoatrial nodes.
The endocrine system consists of the glands and hormones of the human body. The cardiovascular system is the organ system which is responsible for the circulation of the blood around the body and the oxygenation of the body's tissues. The sinoatrial node (SA node) generates the electrical impulses and is considered the natural pacemaker of the heart.
Answer:
A. motor neurons; peripheral nervous system
Explanation:
Motor neurons carry signals from the peripheral nervous system to the muscles. This causes the muscles to either relax or contract. Note that the peripheral nervous system consists of neurons and parts of neurons outside of the central nervous system which consists of the brain and spinal cord. When signals are transmitted between the motor neurons and peripheral nervous system, this causes a response to stimulus in the muscles which would either, relax or contract.
